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DESCRIPTIONS 


OF 


KEW  SPECIES  OF  FOSSILS, 


FROM  THE 


PALAEOZOIC  ROCKS  OF  THE  WESTERN  STATES. 


By  J.  H.  McCHESNEY. 


EXT.  TRANS.  CHICAGO  ACADEMY  OF  SCIENCES,  Vol.  I. 


VAN  BENTIIUYSEN  S PRINT,  ALB,\NY. 


The  following  descriptions  of  new  fossils,  by  J.  H. 
McChesney,  of  Springfield,  Illinois,  are  part  of  those 
noticed  at  a meeting  of  the  Chicago  Academy  of  Sciences, 
on  the  eleventh  of  October  of  this  year ; the  remainder  of 
them  will  be  distributed  in  connection  with  a reprint  of 
these,  as  soon  as  the  engravings,  illustrative  of  them,  can 
be  completed. 

These  beautiful  species,  though  a portion  of  them  were 
collected  from  other  States,  are  all  characteristic  of  rocks 
which  have  their  equivalents  in  Illinois. 


17'^  5 82 


I' 

- i 

I 


CKINOIDEA. 


Plalycsiims  oriiogmiiulus  (n.  s.). 

The  calyx  of  this  crinoid  is  a broad  and  shallow  cup ; 
its  base  of  medium  size,  pentangular,  and  having  the  suture 
lines  barely  visible  ; entire  surface  flat;  edges  not  beveled. 
First  radial  plates  wider  than  high,  their  lower  margins 
straight,  sides  rapidly  spreading  above  ; superior  lateral 
angles  from  the  edges  of  the  cicatrices  for  the  attachment 
of  the  arms  to  their  outer  edges  are  short,  the  entire  plate 
having  a general  subquadrangular  outline,  its  upper  portion 
slightly  curved  inward ; articulating  scar  shallow,  sub- 
semicircular in  form,  and  occupies  about  one  half  the  entire 
width  of  the  plate,  edge  but  little  raised  above  the  general 
surface  of  the  plate.  Second  radials  small,  in  some  in- 
stances scarcely  filling  the  cicatrix  of  the  first  radial; 
sustaining  on  each  of  their  upper  sloping  edges  small  supra- 
radials  in  double  series.  First  bifurcation  of  the  arms  occurs 
on  the  second  supraradial  plate,  and  again  on  the  second 
plate  above  on  the  inner  branch,  giving  three  arms  to  each 
of  the  two  main  divisions  of  the  ray,  or  thirty  to  the  entire 
individual.  Arms  composed  of  a double  series  of  thin 
j)lates,  which  are  obtusely  wedge-form  at  their  interlock- 
ing edges.  Anal  and  interradial  plates  unknown. 

Surface  of  the  plates  entirely  and  closely  covered  by 
small  spiniform  granules,  which  on  the  base  are  directed 
outward,  and  on  the  first  radial  plates  downward.  The 
surface  of  the  arm  plates  is  traversed  by  very  fine  lon- 
gitudinal lines  or  ridges  which  take  their  rise  from  the 


B 


CRINOIDEA. 


receding  angles  of  the  strife  or  notches  of  the  articulating 
faces  of  each  plate,  causing  those  of  one  plate  to  alternate 
with  those  of  the  adjoining  ones ; these  can  only  be  seen 
by  the  aid  of  a lens. 

Column  round,  of  medium  size  ; central  perforation 
minute. 

This  species  is  closely  allied  to  P.  shumardanus  (Geo.  Rep.  Towa,  Vol.  I,  Part 
2,  PI.  viii,  fig.  5),  from  which  it  dilfers  in  several  important  particulars.  The  base 
of  that  species  is  quite  concave  ; the  upper  part  of  the  first  radial  much  more 
abruj)tly  and  distinctly  curved  inward  ; the  cicatrix,  for  the  attachment  of  the 
second  to  the  first  radial  plate,  is  deeper  and  extends  down  farther  on  the  plate,  its 
border  is  more  elevated  above  the  surface  of  the  plate,  and  the  edges  of  all  the  plates 
o.'  the  cah'x  are  beveled.  The  basal  and  first  radial  plates  of  that  species  are 
marked  with  a limited  number  of  small  but  distinct  nodes,  arranged  in  lines, 
instead  of  the  thickly  set  granules  of  this  species. 


? 

Giological  position  and  locality,  Tn  the  Burlington  division  of  the  Carboniferous 
limestone  series,  Burlington,  Iowa 


Body  broad  cup-shaped,  moderately  spreading  from  the 
base  upward.  Basal  plates  unequal  in  size,  very  convex, 
themselves  forming  a low  shallow  enp  of  abont  one  third 
the  entire  height  of  the  calyx ; upper  margins  somewhat 
inflected.  First  radial  plates  much  wider  than  high, 
inereasing  rapidly  in  width  from  below  to  their  upper 
margins,  at  which  point  they  are  slightly  incurved,  very 
unequal  in  size,  the  anterior  plate  being  one  fourth  larger 


a 


The  accompan3nng  diagram  illustrates  the  form  and  propor- 
tions of  the  basal  and  one  of  the  first  radial  plates  ; the  size  of 
the  articulating  scar  ; the  small  .second  radial;  and  also  the 
form,  relative  size,  and  positions  of  the  plates  of  the  arms  of 
one  ray  to  beyond  the  last  bifurcation. 


Platycrimis  iiioritatiis  (n.  s.). 


CRINOIDEA. 


7 


than  the  postero-lateral  one  ; the  articulating  scar  occupies 
about  one  third  the  width,  extending  a little  more  than 
one  third  the  depth  of  the  plate,  and  is  a little  protruding, 
giving  greater  convexity  to  the  j)late  above  than  it  pos- 
sesses below. 

Surface  of  plates  destitute  of  ornaments  or  markings, 
except  a scarcely  perceptible  crescent-shaped  depression 
below  the  articular  facet,  and  the  channel  along  the  line 
of  sutime  bounding  the  radial  plates,  which  are  broad  and 
well  defined.  The  divisions  of  the  basal  plates  are  not 
grooved  or  channeled,  but  smooth.  Summit  and  arms 
unknown. 

This  species  is  most  nearly  related  to  P.  pikiforinis  of  Hall,  and  P.  planus  of 
Owen,  from  the  former  of  which  it  is  distinguished  by  its  short  wide  radial  plates, 
which  in  a specimen  of  P.  pihiformis,  of  the  same  diameter,  are  nearly  twice  the 
height  of  those  in  this  species;  and  the  lines  of  suture  in  that  are  not  channeled  as 
in  this.  The  distinctions  between  this  and  P.  planus  are  nearly  the  same  as  above. 


The  accompanying  diagram  gives  the  form  and  size  of 
the  basal,  and  first  radial  plates  ; as  well  as  the  extent  of 
the  cicatrix  for  the  attachment  of  the  second  radial. 


Geological  position  and  locality.  In  Burlington  division  of  the  Carboniferous 
limestone,  Monmouth  (Illinois),  Burlington  (Iowa.) 


Scaphioci’inus  loiigldactylus  (n.  s.). 

Body  narrowly  turbinate,  slightly  expanding  toward  the 
top  of  the  first  radial  plates  ; base  truncate.  Basal  plates 
large  for  specimens  of  this  genus,  pentagonal  in  form, 
height  and  width  about  equal,  greatest  width  near  the  top 
of  the  plate.  Subradial  plates  nearly  four  times  the  size 
of  the  basal  plates,  four  of  them  hexagonal ; the  fifth, 
which  is  situated  on  the  right  side  of  the  anal  series,  is 


8 


CIUNOIUEA. 


hoptagonal.  First  radial  plates  once  and  a half  as  wide  as 
liigh,  pentagonal  and  having  one  of  the  upper  lateral  angles 
very  slightly  truncated  hy  the  corresponding  angles  of  the 
second  radial  plates.  The  second  radial  plate,  situated  on 
the  righthand  side  of  the  anal  series,  has  the  same  num- 
ber of  angles  with  the  other  four,  hut  is  of  a different  form 
in  consequence  of  its  resting  one  side  on  the  first  anal 
})late.  The  second  radial  plates  are  of  the  form  peculiar  to 
this  group  of  crinoids  ; length  of  the  base  e(|ual  to  the 
greatest  width  of  the  first  radials  ; they  rapidly  contract 
up  to  the  middle,  where  they  are  not  more  than  half  the 
width  of  the  base,  above  which  they  slightly  expand  again 
to  the  base  of  the  sloping  angles  which  support  the  first 
plates  of  the  arms.  The  first  arm  plates  are  nearly  as  long 
as  two  of  the  succeeding  ones. 

Arms,  two  from  each  ray,  simple  from  their  origin,  and 
composed  above  the  first  joints  of  short  wedge-form  plates, 
of  which  there  are  about  twenty  to  the  inch ; their  upper 
edges  are  slightly  reflected,  giving  a rough  zigzag  appear- 
ance to  the  surface  of  the  arms  : the  inside  of  these  plates 
are  deeply  grooved,  and  the  tentacula  are  composed  of 
strong  joints  of  about  the  length  of  the  longest  side  of  the 
arm  joints  to  which  they  are  articulated.  The  number  of 
joints  in  the  tentacula  cannot  be  determined  from  the  spe- 
cimen from  which  the  description  is  drawn.  At  about  two 
and  a half  inches  from  the  base  of  the  arms  there  are 
several  sijine-bearing  plates  visible,  which  appear  to  be 
the  summit  plates  of  the  proboscis  ; if  so,  it  would  give  a 
proboscis  of  about  two  and  a half  inches  in  length. 

Column,  a small  portion  of  which  remains  attached  to 
the  specimen,  is  composed,  near  the  body,  of  thin  joints 
beautifully  sculptured  on  their  articulating  faces,  pentan- 
gular in  form;  central  perforation  pentalobate. 


CEINOIDEA. 


9 


Tlie  accompanying  diagram  illustrates 
the  form,  arrangement,  and  character  of 
the  plates  of  the  body,  and  a portion  of 
the  arms  of  a nearly  entire  specimen  of 
this  species.  The  extent  of  the  incurving 
of  the  sides  of  the  radial  plates  is  also 
shown ; the  remaining  anal  plates  are  hid- 
den by  the  overlapping  of  the  arms  of  the 
postero-lateral  rays. 


Geological  position  and  locality.  In  the  Kaskaskia  division  of  the  Carboniferous 
limestone,  Kaskaskia,  Illinois. 


Zeacriims  bifiircatus  (n.  s.). 

Body  and  arms,  when  closed,  of  a somewhat  cylindrical 
form,  the  calyx  alone  forming  a low  cup,  with  the  base 
rather  deeply  impressed.  The  basal  plates  are  small  and 
entirely  concealed  by  the  column,  which  is  inserted  in  the 
cavity  of  the  base.  Sub  radial  plates  a little  longer  than 
wide  ; four  of  them  hexagonal,  and  one  heptagonal,  by 
the  truncation  of  one  of  its  lateral  angles  by  the  first  anal 
plate.  First  radial  plates  much  wider  than  high,  pentago- 
nal or  hexagonal.  Second  radials  of  about  the  same  size  as 
the  first,  and  obtusely  wedge-formed  above,  except  on  the 
anterior  ray,  where  there  are  two  additional  radial 
plates  inserted  between  the  first  and  third,  or  bifurcating 
plate.  These  bifurcating  plates  give  origin  to  two  arms 
each,  which  are  composed  of  short  quadrangular  plates, 
rather  more  than  twice  the  width  of  their  length.  These 
arms  bifurcate  again  on  the  fourth  or  fifth  plate  above  their 
origin,  and  again  several  plates  higher  up  : the  jirecise 
number  cannot  be  determined  from  the  specimen  under 
description. 


2 


10 


CllINOIDEA. 


Anal  plates  small ; the  first  one  hexagonal  and  elongated 
below,  resting  upon  the  two  adjoining  subradials,  and  sup- 
ported on  the  sides  by  the  adjacent  first  radial  ; on  its 
upper  edges  it  supports  the  two  small  j^lates  of  the  next 
range  ; the  remaining  anal  plates  have  been  broken  away. 

Column,  where  it  joins  the  body,  fills  the  cavity  of  the 
base,  and  is  composed  of  alternately  thick  and  thinner 
joints,  which  are  coarsely  notched  at  the  outer  margins  of 
their  articulating  surfaces. 

This  species  differs  from  Z.  maniformis  of  Shumard,  in  having  compound  arms 
instead  of  simple,  as  well  as  in  the  proportionate  size  of  the  plates;  from  Z.  mag- 
noliaformis  of  Troost,  in  not  having  the  subradial  and  radial  plates  elongated  as 
in  that  species,  nor  the  cavity  of  the  base  so  profound.  Its  nearest  relations  are 
with  Z.  wortheni  of  Hall  (Geo.  Eep.  Iowa,  p.  683),  from  which  it  differs  in  the 
depth  of  the  basal  cavity,  in  the  less  elongated  subradial  and  first  anal  plates;  also 
in  having  but  three  radial  plates  in  the  anterior  ray,  instead  of  four  as  in  that  spe- 
cies; and  in  the  body  being  less  robust,  and  the  cup  not  so  deep. 
a 

The  accompanying  figure  illustrates  the  arrangement  as 
well  as  the  form  of  the  plates  of  the  specimen  as  far  as  can 
be  traced,  showing  tho.se  of  the  arm  of  the  antero-lateral  ray 
to  the  third  plate  above  the' second  bifurcation  The  pecu- 
liarity of  possessing  four  radial  plates  in  the  anterior  ray  and 
but  two  in  each  of  the  others,  is  a distinguishing  feature  of 
this  fo.ssil. 

Geological  position  and  locality.  In  the  Kaskaskia  division  of  the  Carboniferous 
limestone  series,  Kaskaskia,  Illinois. 


Zeacriiius  iimcrosiiiims  (n.  s.). 

Body  forming  a shallow  cup,  the  centre  of  which  is 
deeply  impressed,  the  impressed  portion  consisting  of  the 
basal  and  lower  half  of  the  subradial  plates.  Basal  plates 
small,  pentagonal,  forming  the  bottom  of  the  basal  eavity, 
and  projecting  beyond  the  circumference  of  the  column. 
Subradials  elongate,  height  once  and  a half  the  width, 
greatest  diameter  one  third  the  length  from  the  lower 
margin ; in  form,  three  hexagonal  and  two  heptagonal  : 
the  ujiper  edges,  which  support  the  first  radiaL,  are  more 


CRINOIDEA. 


11 


or  less  curved.  First  radial  plates  large,  heptagonal, 
pointed  below  ; faces  slightly  concave  where  they  join  the 
subradials ; varying  in  height,  the  left  postero-lateral  one 
being  the  shortest,  and  the  anterior  one  equal  to  the  long- 
est ; in  width  they  are  nearly  uniform,  and  wider  than 
high  ; middle  slightly  protuberant  a little  below  the  supe- 
rior margin,  from  which  place  they  are  flattened  to  the 
top.  The  form  of  the  second  radial  plates,  if  deprived  of 
the  spine  with  which  they  are  furnished  and  held  in  their 
natural  position,  would  be  pentagonal,  broad,  and  pointed 
at  the  lower  margins,  narrowing  rapidly  upwards  to  the 
base  of  the  sloping  edges,  nearly  twice  as  wide  as  high  : 
when  perfect,  the  body  of  the  plate  is  produced  into  a long 
sharp  spine,  which,  in  the  specimen  from  which  this  de- 
scription is  drawn,  would  measure  seven  eighths  of  an 
inch  in  length.  Each  of  these  plates  supports  (upon  a surface 
which,  in  the  separate  spine,  appears  to  be  flat,  ornamented 
with  elevated  ridges)  two  plates  of  an  irregular  quadrangu- 
lar form,  the  width  of  which  is  double  the  height.  Above 
these,  and  resting  on  the  outer  part  of  their  articulating 
surfaces,  are  two  small  wedge-formed  plates,  one  above  the 
other.  The  next  plate  is  irregular  in  form,  and  nearly  as 
large  as  the  quadrangular  plate,  and  resting  partly  upon 
it  and  partly  upon  the  small  wedge-formed  plates  ; this  is 
a bifurcating  plate,  and  supports  a series  of  smaller  plates 
which  are  variable  in  size  and  shape,  mostly  wedge-form 
and  six  in  number,  the  last  of  which  is  also  a bifurcating 
plate,  and  gives  support  to  two  sets  of  small  arm  plates, 
the  number  of  which  are  not  determinable  in  the  specimen. 
Anal  plates  (four  of  which  are  preserved)  are  arranged  as 
in  Poteriocrinus ; the  first  pentangular,  three  times  as  long 
as  wide,  the  longest  faces  curved ; one  convex,  the  other 
concave,  resting  upon  two  subradials  and  against  the  first 
radial  of  the  left  postero-lateral ; the  others  are  elongate 
hexagonal,  and  differing  in  size. 


12 


CRINOIDEA. 


Column,  a part  of  which  is  preserved,  is  comparatively 
small,  elliptical  in  outline,  and  composed  of  thick  and 
thin  joints  alternately  ; the  thick  ones  projecting  beyond 
the  others  in  a rounded  rim  ; the  articulating  faces  of  the 
joints  are  deeply  notched  or  striated. 

The  peculiarities  of  this  singularly  interesting  crinoid  consist,  not  only  in  the 
spines  of  the  second  radial  plates,  hut  also  in  the  peculiar  structure  and  arrange- 
ment of  the  arms  from  this  point  upward  to  the  place  of  the  second  bifurcation.  'J  he 
outer  ends  of  the  plates  of  each  main  division  of  each  ray  between  these  points  are 
articulating  faces,  and  are  joined  to  the  corresponding  portion  of  the  adjacent  ray; 
and  thereby  arching  over  the  interradial  spaces  by  a structure  composed  of  the  half 
of  each  ray,  and  forming  by  their  union  the  base  of  one  set  of  arms  which  are  free 
above.  It  is  altogether  probable  that  the  portions  of  the  postero-lateral  rays  which 
are  next  the  anal  side  are  not  articulated  in  this  manner,  but  form  of  themselves 
each  a distinct  and  independent  set  of  arms.  The.se  characters  are  quite  sufficient 
to  distinguish  this  crinoid  from  any  other  heretofore  described,  when  the  spinose 
plates  or  any  portion  of  the  arms  are  preserved ; and  in  their  absence,  the  form  of 
the  subradial  plates  will  alone  determine  its  character.  . 


The  accompanying  diagram  illustrates  the  form  and  proportions  of  the  plates  and 
structure  of  the  body,  and  part  of  one  arm  of  the  anterior  ray  of  this  species.  The 
dotted  lines  on  the  first  radial  plates  show  the  extent  of  the  flattened  portion  of  the 
plate  : a illustrates  the  second  radial  plate,  as  it  would  appear  when  in  position 
without  the  spine;  h,  the  same  with  the  spine  perfect;  c,  the  main  division  of  one  of 
the  rays  from  above  the  second  radial  plate,  and  extending  as  far  as  it  can  be  traced 
in  the  specimen;  the  right  hand  side  of  this  part  of  the  figure  shows  the  articulating 
faces  which  join  those  of  the  adjacent  ray:  d,  the  front  of  the  arm,  showing  the 


CEINOIDEA. 


13 


manner  in  which  the  first  hifiircation  is  produced.  Fip:.  1 is  the  quadrangular  plates 
which  rest  upon  the  upper  surfaces  of  the  second  radials;  fig.  2,  the  first  hifui  cating 
plate  above  the  second  radial;  and  fig.  3,  the  second,  abovb  which  point  the  arms 
are  free  and  movable. 

Geological  position  and  localities.  The  specimen  from  which  the  de.scription  is 
drawn  was  found  in  rocks  of  the  Coal  measures  at  Cai  linville,  Macoupin  county, 
Illinois;  but  I have  found  spines  and  other  fragments  belonging  to  the  same  form  at 
the  mouth  of  Rush  creek,  Indiana,  and  in  Sangamon  county,  and  other  places  in 
Illinois. 

Note.  This  remarkable  Crinoid  belongs  more  nearly  to  the  genus  Zeacrinus  than  to  any 
other  established  genus ; but  if  a sufficient  number  of  specimens  should  be  found,  with  spe- 
cific differences,  having  the  marked  peculiarities  of  this  specimen  constant,  they  may  become 
of  generic  importance. 


Actiiiocsinius  asteiiiis  (n.  s.). 

Body  of  medium  size,  rather  robust,  subturbinate,  trun- 
cate at  the  base.  Arms  proceeding  from  the  base  in  strong 
horizontal  lobes,  or  branches,  which  commence  at  the  third 
radial  plates,  and  give  a remarkable  pentalobate  appear- 
ance to  the  fossil.  Basal  plates  comjiaratively  large,  thick- 
ened at  their  lower  margins,  forming  a transverse  ridge  or 
node  on  each  plate,  giving  a tripartite  base  ; excavated 
beneath  for  the  reception  of  the  column.  First  radial  plates 
comparatively  large,  the  height  from  the  base  of  the  calyx 
to  their  upper  margin  equal  to  half  that  of  the  entire 
calyx.  Second  radials  very  much  smaller,  hexagonal  in 
form,  height  equal  to  two  thirds  their  width ; the  upper 
and  lower  lateral  edges  of  the  same  size.  Third  radials 
almost  equaling  the  second  in  size,  mostly  heptagonal, 
supporting  upon  each  of  their  upper  sloping  edges  a large 
sized  supraradial  plate  which  is  also  a bifurcating  plate, 
and  sustains  on  its  outer  sloping  edge  a series  of  brachial 
plates,  the  second  of  which  appears  to  be  excavated  for 
the  reception  of  the  first  of  the  arm  plates  ; on  the  inner 
sloping  edge,  it  supports  other  bifurcating  supraradials ; 
these  in  turn  support  on  their  inner  edges  brachials,  and 
on  the  outer  supraradials,  giving  eight  arms  to  the  ray. 


14 


CRINOIDEA. 


This  arranj^ement  can  only  be  traced  on  the  postero-lateral 
rays,  the  others  being  l)roken  away  just  above  the  third 
radial  plates ; but  from  the  comparative  size  of  the  open- 
ings, it  is  probable  that  the  antero-lateral  rays  have  about 
the  same  arrangement,  while  the  anterior  ray  was  proba- 
bly smaller.  The  plates  on  the  sides  of  the  ray  above  the 
second  bifurcation  are  bent  upward  at  their  outer  margins, 
and  unite  with  the  plates  forming  the  top  of  the  ray.  First 
interradial  plate  somewhat  regularly  hexagonal,  of  nearly 
the  same  diameter  as  the  second  radials,  supporting  two 
smaller  hexagonal  plates  in  the  second  range,  and  live 
irregularly  formed  plates  in  the  third,  the  outermost  of 
which  rest  also  upon  the  supraradials,  and  are  united 
above,  as  are  the  other  three,  with  the  plates  of  the  crown. 
Anal  area  large  ; the  first  plate  hexagonal,  almost  equal- 
ing the  first  radials  in  size  ; supporting  two  smaller  plates 
in  the  second  range,  one  hexagonal,  the  other  heptagonal, 
and  four  still  smaller  in  the  third  range,  with  a greater 
number  of  narrow  elongated  ones  in  the  fourth,  which  unite 
above  with  the  plates  of  the  dome. 

Surface  of  the  plates  marked  by  strong  angular  ridges ; 
those  of  the  first  radial,  and  anal  plates,  which  join  those 
of  the  basal  plates,  are  two  or  three  in  number,  and  meet 
in  the  centre  of  the  plate,  forming  prominent,  slightly 
transverse  nodes  ; while  those  above  are  single,  and  form 
rounded  tubercles  where  they  meet  in  the  centre  of  the 
plate.  The  plates  above  the  third  radials  are  produced  in 
the  middle,  and  form  ramifying  ridges,  running  along  the 
different  divisions  of  the  ray. 

The  dome,  which  is  but  little  elevated,  is  terminated  b}'- 
a very  strong  central  proboscis,  and  composed  of  rather 
large  polygonal  plates,  produced  into  elevated  somewhat 
rounded  tubercles  ; which  character  is  also  extended  to 
those  forming  the  roof  of  the  arm  bases,  or  lobes. 


CRINOIDEA. 


15 


Tliis  species  is  of  the  type  of,  and  closely  allied  to  A.  lowei  of  Hall  (Geo.  Kept. 
Iowa,  pi.  15,  fig.  5),  but  dilTers  from  it  in  the  greater  lieight  in  proportion  to  its 
width,  and  in  the  mode  of  growth  and  arrangement  of  plates  in  the  arm  bases,  this 
species  being  destitute  of  the  intervening  plates,  between  the  bifurcating  ones,  and 
also  in  its  not  possessing  inter-supraradials  between  the  main  divisions  of  the  ray. 
Both  of- the  last  mentioned  characters  are  marked  peculiarities  of  that  species,  as 
may  be  seen  by  the  diagram  accompanying  the  description.  The  proboscis  is  also 
smaller,  and  the  tubercles  of  the  dome  are  neither  so  numerous  nor  strong  as  in  that 
species. 

a 


The  accompanying  diagram  illustrates 
the  form,  size,  and  relative  positions  of 
the  arms  of  the  postcro-lateral  rays,  as 
far  as  can  be  a.scertained  from  the  spe- 
cimen. The  great  number  of  six-sided 
plates  in  the  interradial  and  anal  series 
form  a remarkable  feature  in  this 
species. 


Geological  position  and  locality.  In  the  Burlington  division  of  the  Carboniferous 
limestone,  Monmouth,  Illinois. 

Actiiiocriluis  teimisciilptus  (n.  s.). 

Body  below  the  arms  distinctly  turbinate  ; base  truncate, 
and  slightly  concave  for  the  insertion  of  the  column.  Basal 
plates  of  medium  size,  slightly  thickened  at  their  lower 
margins,  and  forming  of  themselves  a very  shallow  cup. 
First  radial  plates  largest,  hexagonal  and  heptagonal,  a 
little  wider  than  high ; the  upper  and  lower  lateral  angles 
nearly  equal.  Second  radials  considerably  smaller  than 
the  first,  hexagonal,  width  once  and  a half  the  height. 
Third  radials  larger  than  the  second,  somewhat  wider  than 
high,  hexagonal  and  heptagonal,  and  supporting  upon  each 
of  their  upper  sloping  edges  a hexagonal  supraradial  plate 
of  large  size,  which  sustains  upon  its  outer  sloping  edge 


IG 


CfllNOIDEA. 


a .series  of  simple  })raeliial  plates ; while  upon  the  inner 
edge  it  gives  support  to  another  but  smaller  supraradial 
plate,  which  again  supports  two  series  of  brachial  plates, 
giving  three  arms  to  each  main  division ; and  as  all  the 
rays  appear  to  he  furnished  with  a like  number  (as  far  as 
can  be  determined  from  the  specimen),  this  arrangement 
would  give  thirty  arms  to  the  entire  individual. 

The  interradial  series  con.sists  of  seven  or  eight  jolates 
each,  the  first  large,  equaling  in  size  the  second  radials, 
but  more  regularly  hexagonal,  resting  upon  the  upper 
lateral  angles  of  the  first  radials  and  against  the  lower 
lateral  angles  of  the  second  radials,  while  it  supports  upon 
its  upper  angles  two  other  smaller  plates,  one  pentagonal 
and  the  other  hexagonal ; the.se  support  two  still  smaller 
ones  in  the  third  range  and  two  in  the  fourth,  with  some- 
times a small  narrow  or  elongated  plate  situated  between 
the  brachial  plates  of  the  adjacent  rays.  There  are  also 
two  small  elongated  inter-supraradial  plates  situated  be- 
tween the  two  main  divisions  of  each  ray,  the  lower  one 
resting  upon  the  inner  edges  of  the  first  and  between  the 
second  supraradial  plates ; the  .second  of  these  plates  rest 
upon  the  top  of  the  first.  Anal  series  composed  of  twelve 
plates,  the  first  hexagonal,  little  smaller  than  the  radial 
plates,  supporting  two  heptagonal  plates  in  the  second 
series,  which  are  equal  in  size  to  the  second  radials  ; the 
third  range  consists  of  four  plates,  the  fourth  of  three, 
fifth  of  one,  and  one  other  still  higher,  which  separates  the 
brachial  plates  of  the  outer  arm  of  each  postero-lateral 
ray.  Arms  and  summit  unknown. 

Column  at  its  junction  with  the  base  large,  round;  cen- 
tral perforation  at  this  point  large,  pentalobate. 

The  surface  of  this  beautiful  crinoid  is  clal)orately  sculptured,  very  similarly  to 
A.  sculptus  of  Hall  (Geo.  Hep.  Iowa,  PI.  x,  fig.  11);  but  the  markings  are  more 
delicate,  and  the  secondary  set  of  ridges  are  broken  so  as  to  give  them  the  appear- 
ance of  lines  of  beads,  rendering  it  beautifully  ornamental  ; but  in  structure  it  is 
more  nearly  related  to  y/.  ornatus  (figured  on  the  same  plate  with  that  last  men- 


CRINOIDEA. 


17 


tiono(l),  and  its  congeners;  but  differs  from  all  of  them  hitherto  described  in  the 
nature  and  strength  of  the  surface  markings,  as  well  as  in  the  form  of  the  body  at 
the  base  of  the  arms,  this  species  not  having  the  interbrachial  and  interradial  spaces 
sunk  into  deep  channels  and  grooves  as  in  most  of  them.  It  differs  from  Jl.  ornatus 
and  some  others  in  the  number  of  arms,  and  in  the  body  being  more  regularly  tur- 
binate. 


P 

Geological  position  and  locality.  Burlington  division  of  the  Carboniferous  lime- 
stone series,  Columbia,  Missouri. 


Body  regularly  and  broadly  turbinate  below  the  arms, 
above  broadly  conical,  and  terminating  in  a rather  strong 
central  proboscis;  base  somewhat  broadly  truncated. 
Basal  plates  proportionately  large,  much  thickened,  pro- 
jecting below,  and  forming  a trilobed  rim  around  the  top 
of  the  column.  First  radial  plates  nearly  as  wide  again  as 
high,  hexagonal  and  heptagonal.  Second  radials  forming 
only  a narrow  line  between  the  first  and  third  radials, 
quadrangular ; width  full  three  times  the  height.  Third 
radials  rather  small,  pentangular,  and  supporting  upon 
each  of  their  ujiper  sloping  edges  two  broad  short  supra- 
radials,  the  uppermost  of  which  are  bifurcating  plates, 
and  sustain  each  two  sets  of  braehial  plates  in  double 
series ; except  in  the  anal  portions  of  the  postero-lateral 


a 


^ The  accompanying  diagram  illustrates 
the  form  and  arrangement  of  the  plates 
of  the  body  to  the  bases  of  the  arms  of 
a specimen  of  this  species,  and  affords 
a good  opportunity  for  comparison  with 
its  most  closely  allied  species’. 


Actmociliiiis  subspqiialis  (n.  s.). 


3 


18 


CllINOIDEA. 


rays,  where  on  one  side  the  second  supra  radial  plate  sup- 
ports on  its  inner  edge  a double  series  of  brachials,  and  on 
the  outer  a single  secondary  supraradial,  which  gives  sup- 
port on  one  side  to  brachial  plates,  and  on  the  other  to  two 
still  higher  supraradials  : the  uppermost,  being  also  a 
bifurcating  plate,  gives  origin  to  two  more  arms,  making 
six  arms  to  the  ray,  four  of  which  take  their  rise  from  one 
main  division,  while  the  other  main  division  has  but  two 
arms.  The  other  postero-lateral  ray  has  but  five  arms, 
possessing  but  one  extra  bifurcating  plate  : this  arrange- 
ment gives  the  following  brachial  formula  = 23.  This 
is  probably  an  unusual  arrangement,  and  not  the  true  one 
of  the  species,  which  may  be  either  22  or  24.  The  interra- 
dial  plates  are  three  in  each  series ; the  first  one  compara- 
tively large,  ten-sided,  supporting  the  other  two,  which 
are  quite  small,  uj)on  its  upper  angles.  Anal  plates 
seven  or  eight,  irregularly  arranged  ; the  first  one  nearly 
as  large  as  the  first  radial  plates,  heptagonal,  and  supports 
three  in  the  second  range,  the  two  outermost  of  which  are 
large,  the  central  one  small  ; the  other  four  are  irregularly 
placed  above ; one  of  the  middle  ones  large,  situated 
between  the  upper  parts  of  the  adjoining  rays,  and  sup- 
porting the  last  and  outermost  brachial  plates  upon  its 
upper  sides.  The  surface  of  the  basal  and  first  radials  are 
elevated  into  prominent  transverse  nodes  ; that  of  the  third 
radial,  first  interradial,  and  four  of  the  anal  plates,  into 
prominent  rounded  nodes ; and  all  of  the  other  j)lates  of 
the  calyx  are  more  or  less  nodulose,  except  the  second 
radials.  The  plates  of  the  dome  and  proboscis  are  highly 
tuberculose ; they  are  irregular  in  size  and  form,  and  the 
nodes  are  angular,  the  ridge  being  in  the  direction  of  the 
longest  diameter  of  the  node.  The  articulating  facet  for 
the  attachment  of  the  column  is  round,  large,  somewhat 
deeply  sunk  into  the  cavity  of  the  basal  plate  : central 
perforation  round,  minute.  Column  and  arms  unknown. 


CRINOIDEA. 


19 


This  species  is  somewhat  closely  related  to  A.  (zqualis 
of  Hall  (Geo.  Hep.  Iowa,  PL  xi,  fig.  4),  but  is  more  ele- 
vated in  comparison  with  its  diameter,  the  surface  arrange- 
ments differently  disposed,  the  third  radial  and  first  bifur- 
cating supraradial  plates  having  distinct  nodes,  which  that 
species  does  not  possess  ; and  the  arrangement  of  the  arms, 
as  well  as  the  difterence  in  number,  is  entirely  distinct, 
the  formula  of  that  species  being  = 26  arms,  while 
this  has  probably  not  more  than  twenty-two. 

a 

The  diagram  illustrates  the  form,  size  and  arrange- 
ment of  the  plates  of  the  body  to  the  bases  of  the  arms 
of  a specimen  of  this  species.  The  very  short  second 
radial  plates  form  a peculiar  feature.  The  additional  arm 
e on  the  right  postero-lateral  ray  is  probably  due  to 
dent  and  not  a specific  character,  the  number  being 
twenty-two. 

Geological  position  and  localities.  In  the  Burlington  division  of  the  Carboniferous 
limestone  series,  Monmouth  (Illinois),  and  Burlington  (Iowa). 


Actinocriims  fosteri  (n.  s.). 

The  calyx  of  this  species  is  broadly  turbinate,  expand- 
ing rapidly  from  below  upward  to  the  base  of  the  arms, 
where  the  diameter  is  one  third  greater  than  the  height ; 
base  truncate  or  concave.  Basal  plates  quite  low,  slightly 
thickened  at  their  lower  margin,  so  as  to  form  a perpen- 
dicular rim  to  the  cup.  First  radials  of  medium  size,  rather 
wider  than  high  ; upper  lateral  angles  large.  Second  radi- 
als little  more  than  half  the  size  of  the  first,  hexagonal, 
except  that  in  the  right  postero-lateral  ray,  which  is 
pentangular ; width  greater  than  the  height,  irregular  in 
shape  and  size.  Third  radials  hexagonal,  being  truncated 
above  by  a large  sized  polygonal  inter-supraradial  plate. 
Upon  each  of  the  lateral  sloping  angles  of  the  third  radials 
rests  a single  supraradial  plate  of  about  two-thirds  the 


20 


CRINOIDEA. 


size  of  the  tliird  radials,  and  sustaining  upon  its  outer 
sloping  edges  a series  of  brachial  plates,  two  of  which 
remain  on  some  of  the  rays  in  the  specimen  ; ujion  its 
inner  sloping  edges  it  supports  a supraradial  of  the  second 
order,  which  in  turn  gives  origin  to  two  sets  of  brachial 
plates,  making  three  arms  to  each  principal  division  or  six 
to  each  ray,  equal  to  thirty  to  the  entire  individual.  First 
interradial  jDlates  hexagonal,  size  rather  larger  than  that 
of  the  second  radials,  supporting  on  its  upper  edges  two 
smaller  plates,  one  of  which  is  hexagonal,  the  other  hep- 
tagonal  ; in  each  series  above  these  there  are  five  and 
sometimes  six  smaller  polygonal  plates,  irregularly  placed, 
the  uppermost  of  which  is  a narrow  elongated  plate,  and 
situated  high  up  between  the  upper  brachial  plates  of  the 
adjacent  rays  dividing  them,  and  is  generally  wider  at  the 
top  than  below. 

Anal  series,  in  the  specimen  under  examination,  consists 
of  thirteen  plates,  the  first  of  which  is  hexagonal,  some- 
what smaller  than  the  first  radial  plates ; sides  nearly 
parallel  : the  two  succeeding  plates  are,  one  hexagonal,  the 
other  heptagonal,  as  large  or  larger  than  the  second  radials ; 
the  third  range  consists  of  four  small  plates,  the  outer  arms 
of  which  rest  against  the  third  radials  ; in  the  fourth  range 
there  are  three  plates  only,  and  in  the  fifth  but  two  ; a 
single  plate  above  and  between  them,  which  separates  the 
brachial  plates  of  the  postero-lateral  rays. 

The  centres  of  all  the  plates  are  more  or  less  convex, 
and  traversed  by  ridges  which  are  compound  on  the 
radial  plates  and  single  on  the  others;  these  ridges  meet 
at  or  near  the  centre  of  the  plate,  and  form  pointed  angu- 
lar nodes,  increasing  in  comparative  size  as  they  reach  the 
upper  portion  of  the  calyx.  The  node  on  the  plate  situated 
immediately  above  the  third  radial  plate  is  remarkably 
conspicuous. 


CRINOIDEA. 


21 


This  species  is  related  to  A.  multibrachiatus  and  A.  proboscidialis  of  Hall  (Geo. 
Rep.  Iowa,  PI.  x,  figs.  10  and  13);  but  differs  from  any  of  that  type  heretofore 
described,  in  the  number  and  arrangement  of  the  arms  and  rays,  and  also  in  the 
form  and  proportions  of  the  body. 
a 


The  accompanying  diagram  is  from  a 
specimen  of  this  species,  and  illustrates  the 
form  of  the  plates  to  the  bases  of  the  arms. 
The  very  large  inter-supraradial  plates, which 
truncate  the  top  of  the  third  radial  plate,  is  a 
distinguishing  feature  which  is  not  possessed 
by  any  other  species  of  this  group  to  such  a 
remarkable  extent,  as  in  this  one. 

P 

Geological  position  and  locality.  In  the  Burlington  division  of  the  Carboniferous 
limestone  series,  Burlington,  Iowa. 


Actiiiociiims  SMbveiitricosiis  (n.  s.). 

The  calyx  of  this  crinoid  is  turbinate,  with  the  sides 
somewhat  inflated ; summit  depressed  convex,  rising 
abruptly  at  the  edges  and  flattened  in  the  centre.  Base 
small ; basal  plates  being  but  little  larger  than  the  column 
at  the  junction,  and  expand  gradually  to  their  superior 
edges,  at  which  point  the  inflation  of  the  sides  of  the  cup 
commences.  First  radial  plates  largest,  two  heptagonal 
and  three  hexagonal,  the  superior  lateral  angles  being  the 
longest.  Second  radials  hexagonal,  higher  than  wide,  great- 
est width  below  the  centre.  Third  radials  as  large  as  the 
second,  heptagonal  in  form,  height  equal  or  greater  than 
the  width ; sustain  upon  their  upper  sloping  angles  siijira- 
radials  of  medium  size,  which  in  shape  are  mostly  hep- 
tagonal. These  plates  support  on  their  outer  angles  a series 
of  brachial  plates,  three  of  which  are  visible  in  the  speci- 
men ; on  their  inner  angles  they  support  supraradials  of 


22 


CRINOIDEA. 


the  second  degree,  very  small  in  size,  but  which  support 
other  series  of  plates  on  each  of  their  upper  sloping  edges  ; 
on  the  one  simple  brachial  plates,  while  on  the  other  the 
second  is  a bifurcating  plate,  and  gives  rise  to  two  arms ; 
which  make  four  arms  from  each  main  division  of  each 
ray,  or  eight  arms  to  the  entire  ray.  The  interradial  series 
consists  of  nine,  and  in  some  instances  ten  plates,  the  first 
of  which  is  hexagonal,  equaling  in  size  the  second  radials, 
resting  upon  the  superior  lateral  angles  of  the  first  radials, 
and  flanked  on  its  sides  by  the  second  radial,  while  upon 
its  upper  edges  it  sustains  two  smaller  plates  in  the  second 
range,  two  in  the  third,  fourth,  and  fifth  ranges  each ; 
which  plates  gradually  decrease  in  size  as  they  rise,  the 
highest  being  very  small  : the  tenth  plate,  when  it  exists, 
is  minute,  and  situated  high  up  between  the  brachial  of 
the  adjacent  arms. 

Anal  plates,  but  three  remain  in  the  specimen  from 
which  the  description  is  drawn,  but  in  other  specimens  of 
the  species  they  are  from  thirteen  to  fifteen  in  number; 
the  first  is  hexagonal  and  of  the  size  of  the  second  radials, 
and  supports  two  in  the  second  range  : the  other  ranges 
consist  of  three,  three,  three,  two  and  one  respectively. 
These  plates  appear  to  be  subject  to  some  variation 
both  in  number  and  arrangement,  but  are  generally  of  an 
hexagonal  form,  and  decrease  in  size  from  below  upward ; 
the  uppermost  being  very  small,  as  in  the  case  of  the 
interradials. 

The  surface  of  all  of  the  plates  of  this  crinoid,  except 
those  of  the  summit,  are  tumid  or  highly  convex,  and  tra- 
versed by  a number  of  ornamental  ridges,  which,  on  the 
centre  of  the  plates,  are  faint,  but  where  they  pass  from 
plate  to  plate  they  are  very  sharp  and  well  defined,  having 
deep  punctures  between  them,  which  in  some  weathered 
specimens  appear  to  pass  into  the  interior  of  the  test. 


CRINOIDEA. 


23 


Compared  -with  A.  ventricosus  of  Hai.l  (Iowa  Rep.  Vol  I,  PI.  xi,  fig.  fi),  which 
it  closely  resembles,  it  is  a more  lofty  form,  caused  by  the  several  ranges  of  plates 
being  much  higher  in  proportion  to  their  width  than  in  that  species  : the  interradial 
and  anal  series  consist  of  one  or  two  more  ranges  of  plates;  the  basal  plates  are 
also  much  longer.  The  dome  of  this  species  is  not  elevated  as  in  that,  being  in  most 
instances  nearly  flat  or  but  slightly  convex,  and  is  not  cut  up  by  such  deep  channels 
as  is  that  of  A.  ventricosus.  On  the  summit  of  the  dome,  there  is  a small  anal 
opening  situated  subcentrically  nearest  to  the  anal  side.  Arms  and  column  un- 
known. 

Geological  position  and  locality.  In  the  Burlington  division  of  the  Carboniferous 
limestone  series  : Burlington,  Iowa. 


Actiiioeiiims  iini?eforiHis  ( n.  s.). 

Body,  below  the  arms,  narrowly  turbinate ; the  greatest 
diameter,  which  is  at  the  point  of  attachment  of  the  arms, 
is  little  more  than  once  and  a half  the  width  of  the  base  ; 
the  summit  is  a dome,  surmounted  by  a sub-central  pro- 
boscis of  comparatively  large  size.  Base  truncate.  Basal 
plates  low,  thickened  at  their  lower  margin,  and  forming 
an  expanding  rim  around  the  base  of  the  cup.  First  radial 
plates  rather  large  in  comparison  with  the  other  plates  of 
the  body,  height  and  width  about  equal ; and  are,  as  are 
also  the  first  and  second  interradial  plates,  furnished  with  a 
central  tubercle  or  subspine,  while  the  other  plates  of  the 
body  are  scarcely  convex.  Second  radial  plates  minute, 
quadrangular  ; width  nearly  twice  the  height.  Third  radials 
pentangular;  but  little  wider  than  high;  slightly  larger 
than  the  second  radials,  supporting  on  each  of  their  supe- 
rior sloping  edges  in  the  anterior  and  antero-lateral  rays  a 
double  series  of  brachial  plates,  and  in  the  postero-lateral 
ray  brachials  on  one  side  and  a single  supraradial  on  the 
side  adjoining  the  anal  area,  which  gives  support  to  a sin- 
gle brachial  on  each  of  its  sloping  edges,  making  the  brachial 
formula  = 14  arms  to  the  entire  specimen.  The  inter- 
radial series  consists  of  but  one  octagonal  plate  in  each 
area,  which  is  comparatively  large,  and  a little  higher  than 
wide,  the  general  form  being  ovate. 


24 


CRINOIDEA. 


Anal  series  consists  of  seven  plates,  the  first  slightly 
larger  than  the  first  radials,  heptagonal,  supporting  three 
in  the  second  range  and  three  in  the  third  range,  the  cen- 
tral one  of  which  is  placed  between  the  brachial  plates  of 
the  adjacent  arras  and  unites  with  the  plates  of  the  dome. 
Dome  composed  of  small  polygonal  plates. 

The  ovarian  apertures,  situated  on  the  outside  of  the 
arm  openings,  are  very  large,  and  may  he  easily  mistaken 
for  another  set  of  arms,  especially  as  the  brachial  plates 
are  slightly  protruding,  and  have  somewhat  the  appearance 
of  bifurcating  plates. 

This  species  has  some  resemhlance  to,  and  has  licretofore  been  confounded  with, 
//.  vanumlii  (Suumaiid),  figured  and  described  in  the  Missouri  Geol.  Report;  but 
it  differs  not  only  in  form,  but  also  in  the  number  and  disposition  of  the  arms. 
That  species  is  described  as  having  fourteen  or  fifteen  arm-openings,  which,  in  one 
instance,  would  give  three  arms  to  each  ray;  and,  in  the  other,  two  to  the  anterior 
and  three  to  each  of  the  other  rays. 

Geological  position  and  locality.  In  the  Burlington  division  of  the  Carboniferous 
limestone.  Honey  creek,  Illinois. 


ActiJiocrIjsiis  hiirdiaims  (n.  s.). 

Body  beloAv  the  arms  urnshaped,  spreading  abruptly 
above  the  first  supraradial,  and  truncate  at  the  base,  which 
is  not  excavated  for  the  reception  of  the  column.  Basal 
plates  very  low,  but  little  thickened.  First  radial  plates 
of  medium  size,  wider  than  high,  the  greatest  width  being 
about  midway  between  the  base  and  summit  of  the  plate. 
Second  radials  hexagonal,  width  one-half  greater  than 
their  height,  a little  more  than  half  the  size  of  the  first 
radials.  Third  radials  hexagonal,  larger  than  the  second 
radials,  height  as  great  or  greater  than  the  width,  support- 
ing on  their  superior  sloping  angles  supraradial  plates, 
which  are  ecpial  in  size  to  the  second  radials  ; these  are 
also  hexagonal,  and  support  on  their  outer  sloping  angles 
a series  of  brachial  plates,  two  of  which  appear  to  aid  in 
forming  the  body  of  the  crinoid,  while  on  their  inner 


CRINOIDEA. 


25' 


angles  they  support  a single  supraradial  plate  of  the  second 
order,  which  gives  origin  to  tAVO  arms  from  its  upper  angles, 
making  three  arms  to  each  division  of  each  ray,  or  six  to 
each  ray,  equal  to  thirty  arms  to  the  entire  specimen.  The 
interradial  series  consists  of  four  hexagonal  plates  in  each 
of  the  postero-lateral  areas ; Avhile  those  of  the  antero- 
lateral areas  are  five  in  number,  one  of  which  is  pentago- 
nal. The  first  interradial  plate  is  of  the  size  of  the  third 
radial.  First  anal  plate  hexagonal,  higher  but  not  so  Avide 
as  the  first  radials  : second  range  consists  of  two  smaller 
plates  which  are  heptagonal,  Avith  five  other  small  plates 
irregularly  scattered  in  above  the  brachial  plates  of  the 
adjacent  rays,  uniting  above.  The  summit  of  the  specimen 
is  high,  dome-shaped,  and  terminates  in  a rather  strong 
central  proboscis,  Avhich  is  surrounded  near  the  base  by  a 
number  of  plates,  some  of  Avhich  bear  short  spines.  The 
remainder  of  the  plates  of  the  dome  are  mostly  small,  a 
few  larger  ones  scattered  promiscuously  amongst  them, 
most  of  which  are  tuberculose.  The  plates  of  the  calyx  are 
tumid,  and  traversed  by  a series  of  sharp  ridges,  Avhich 
meet  in  the  centre  of  the  plate  and  form  stars,  the  num- 
ber of  the  rays  varying  according  to  the  position  of  the 
plate. 

This  species  is  most  nearly  allied  to  Jl.  proboscidialis  of  Hall  (Geo.  Rep.  of 
Iowa),  but  differs  from  it  in  having  six  arms  to  each  ray  instead  of  only  four,  and 
in  the  form  and  proportion  of  the  plates  of  the  cal3fx,  which  is  never  so  much  in- 
flated as  in  that  species.  The  dome  of  this  species  is  composed  mostly  of  small 
plates,  while  that  has  it  built  up  of  large  ones. 

Geological  position  and  locality.  In  the  Burlington  division  of  the  Carboniferous 
limestone  series  : Burlington,  Iowa. 


Actinocriims  iiequibracliiatus  ( n.  s. ). 

Body,  below  the  arms,  broadly  turbinate,  expanding  very 
rapidly  for  the  last  half  of  its  height;  above,  depressed 
convex,  or  a very  short  and  broad  conical  shape,  termina- 
ting in  a medium-sized  subcentral  proboscis,  excentric  on 
4 


C’RINOIDEA, 


2G 

the  anal  side.  Base  small,  truncate,  and  slightly  excavated 
for  the  reception  of  the  column.  Basal  plates  low,  not 
tumid.  First  radials  rather  large  comjiared  with  the  other 
plates,  hexagonal  and  heptagonal ; breadth  and  height 
about  equal,  the  greatest  width  being  near  the  upper  mar- 
gin ; superior  lateral  angles  very  small.  Second  radials 
short;  breadth  once  and  a half  that  of  the  height.  Third 
radials  as  wide  again  as  high,  heptagonal  except  those 
adjoining  the  anal  series,  where  they  are  shortened- one 
angle,  making  them  hexagonal  : they  support,  on  each  of 
their  upper  sloping  edges,  broad  supraradial  plates,  in 
double  series,  the  upper  one  of  which  is  a bifurcating  plate, 
and  supports  two  double  series  of  brachials,  giving  origin 
to  four  arms  to  each  ray,  or  twenty  to  the  entire  individual. 

The  interradial  series  consist  of  nine  plates  in  four  ranges 
of  two  plates  each,  above  the  first  plate,  which  is  large  and 
of  an  octagonal  form,  resting  upon  the  upper  lateral  angles 
of  the  first  radials,  and  flanked  on  the  sides  by  the  second 
and  third  radials.  The  other  interradial  plates  are  much 
smaller,  and  of  various  forms ; the  uppermost  are  smallest, 
and  situated  between  the  highest  brachial  plates  that  con- 
tribute to  form  the  body  of  the  crinoid,  entirely  separating 
them,  and  forming  a shallow  sinus  which  reaches  into  the 
summit  of  the  specimen. 

Anal  series,  in  the  specimen  used  for  description,  consists 
of  thirteen  plates,  the  first  heptagonal,  smaller  than  the 
first  radials,  and  supports  three  smaller  heptagonal  plates 
in  the  second  range  : the  two  next  ranges  form  arches 
above,  the  'first  of  three  and  the  second  of  four  plates 
respectively ; while  above  the  second  of  these  arches,  or 
the  fourth  range  of  plates,  there  are  two  small  plates  which 
separate  the  brachial  plates  of  the  adjoining  rays,  com- 
pleting the  series  of  thirteen  plates,  and  uniting  with  those 
of  the  summit  of  the  specimen. 


CRINOIDEA. 


27 


The  surface  of  the  plates  of  the  calyx  is  slightly  convex, 
while  the  plates  of  the  summit  are  elevated  into  rounded 
tubercles,  those  near  the  base  of  the  proboscis  being  large, 
and  decreasing  in  size  as  they  approach  the  arm  openings. 

This  species  possesses  the  peculiarity  of  having  the  arm  openings  situated  on  the 
summit,  or  opening  upwards,  and  not  on  the  periphery,  as  in  most  species  of  j^cti- 
nocrinus.  The  only  other  species  with  which  I am  acquainted,  possessing  the  same 
character,  is  A.  nashvillcB  (Tkoost),  figured  in  Hall’s  Report  on  the  Geology  of 
Iowa,  Vol.  1,  Part  2. 

Geological  position  and  locality.  In  the  Burlington  division  of  the  Carboniferous 
limestone  series,  Monmouth,  Illinois. 


Actiiiocrlnus  aiidrewsiaiius  ( n.  s. ). 

Body  regularly  turbinate  below  the  arms ; above,  highly 
dome  shaped,  and  surmounted  by  a sub-central  proboscis  of 
medium  size,  the  base  alone  remaining  in  the  specimen 
under  description.  Base  very  small,  and  deeply  excavated 
for  the  reception  of  a small  column.  Basal  plates  not  thick- 
ened. First  radial  plates  of  medium  size,  a little  wider  than 
high.  Second  radials  minute,  as  wide  again  as  high,  quad- 
rangular. Third  radials  pentangular,  except  those  on  the 
posterior  rays,  which  are  hexagonal,  having  an  extra  angle 
on  the  side  adjoining  the  interradial  series  : these  third 
radial  plates  support  on  each  of  their  upper  sloping  edges> 
except  in  the  anterior  ray,  supraradial  plates  in  double 
series,  the  uppermost  of  which  is  a bifurcating  plate,  and 
gives  support  on  each  of  its  sloping  edges  to  a double  series 
of  brachial  plates,  giving  four  arms  to  each  of  these  rays. 
The  third  radial  of  the  anterior  ray  supports  two  double 
series  of  brachial  plates,  giving  rise  to  two,  arms  only, 
making  the  brachial  formula  as  follows  : = 18  arms  to 

the  entire  specimen. 

The  interradial  series  consists  of  three  plates  in  each 
series,  the  first  one  two-thirds  the  size  of  the  first  radials  : 
those  adjoining  the  anterior  ray  are  ten-sided,  while  the 
others  are  but  nine.  Each  of  these  plates  supports  on  its 


28 


CRINOIDEA. 


upper  edges  two  smaller  plates,  which  are  five,  six  or 
seven-sided,  as  the  case  requires,  the  brachial  plates  of  the 
adjacent  rays  resting  upon  their  upper  edges. 

Anal  series  consists  of  but  four  plates,  the  first  one  higher 
but  not  so  wide  as  the  first  radial  plates  ; the  other  three 
form  an  arch  over  the  superior  edge  of  this  plate,  and  are 
flanked  on  their  outer  and  upper  angles  by  the  radial,  supra- 
radial  and  brachial  plates  of  the  adjacent  rays  : the  first 
brachial  plates  of  these  rays  join  each  other  on  their  lateral 
angles,  and  enclose  the  anal  series  beneath  them. 

The  surface  of  the  plates  of  the  lower  part  of  the  crinoid 
is  entirely  smooth  to  the  unassisted  eye ; those  of  the 
dome,  which  are  comparatively  large  polygonal  plates,  are 
slightly  convex. 

Column  unknown ; but  judging  from  the  articulating 
facit  of  the  base  of  the  cup,  it  has  been  very  small,  and 
apparently  round. 

Arms  entirely  unknown,  except  in  number,  which  is 
eighteen. 

Geological  position  and  locality.  In  the  Burlington  division  of  the  Carboniferous 
limestone  series,  Burlington,  Iowa. 


AcdBiociimis  Iiageri  ( n.  s.). 

Body,  below  the  arms,  broadly  sub-turbinate,  having  the 
sides  of  the  base  somewhat  broadly  rounded ; more  rapidly 
spreading  above  the  third  radial  plates  than  below,  and 
again  contracting  at  the  base  of  the  arms.  The  upj:)er  part 
of  the  calyx  is  slightly  pentalobate,  caused  by  the  depres- 
sion of  the  interradial  and  anal  series.  Summit  depressed, 
convex  most  prominent  over  the  anal  area,  where  there  is  a 
small  but  very  prominent  anal  opening.  Basal  j^lates  low, 
of  medium  size.  First  radials  very  large,  half  as  wide  again 
as  high.  Second  radials  quadrangular,  three  times  as  wide 
as  high.  Third  radials  pentagonal  or  hexagonal,  proportion- 
ate width  and  heighth  as  in  second  radials,  and  sustaining 


CRINOIDEA. 


92 


upon  each  of  the  upper  sloping  edges  two  supraradial  plates, 
which  are  not  so  wide  but  much  higher  than  the  plate  on 
which  they  rest ; the  upper  one  of  these  is  wedge-formed 
above,  and  gives  supjiort  to  two  short,  broad  brachial  plates 
on  each  side ; the  upper  one  is  excavated  above  for  the 
insertion  of  the  arm  plates.  This  arrangement  gives  four 
arms  to  each  ray,  or  twenty  to  the  entire  specimen.  First 
interradial  plate  octagonal,  not  very  large,  supporting  two 
smaller  plates  in  the  second  range,  and  in  the  anterior 
series  another  smaller  one  above  and  between  these ; the 
last  three  plates  differ  in  the  number  of  their  angles,  and 
are  of  an  elongate  form.  Anal  series  consists  of  from  seven 
to  nine  plates,  the  first  one  heptagonal,  equal  in  size  to  the 
first  radials,  sustaining  three  in  the  second  range  and  three 
in  the  third,  Avhile  the  remainder  are  placed  above  and 
between  the  brachial  plates  of  the  adjoining  rays. 

Surface  of  the  plates  of  the  entire  body  smooth. 

The  peculiarities  of  this  fossil  consist  in  the  possession  of  an  anal  opening,  which 
is  a feature  seldom  present  in  specimens  of  this  t)^pe,  and  in  the  arm-openings  1 eing 
situated  on  the  edge  of  the  dome  similarly  to  those  of  A.  nashvillce  (Tuoost)  Geo. 
Rept.,  Iowa. 

Geological  position  and  locality . In  the  Burlington  division  of  the  Carboni'.erous 
limestone,  Burlington,  Iowa. 


Forhesiociiims  |{ratteui  ( n.  s.). 

Body  very  large  and  massive,  subglobose  and  indistinctly 
pentalobate,  very  broadly  spreading  from  below  upward  to 
above  the  fi-rst  supraradial  plates,  above  which  point  it  is 
again  contracted.  The  plates  of  the  body  are  very  large, 
most  of  them  highly  covex  or  tumid,  and  bearing  in  the 
centre  on  abruptly  elevated  node  or  subspine,  some  of 
which  are  about  an  eighth  of  an  inch  in  length  and  nearly 
the  same  in  diameter ; giving  rather  a bristling  appear- 
ance to  the  specimen.  The  basal  plates  are  unusually  large 
for  a specimen  of  this  genus,  and,  in  this  individual,  are 


30 


CRINOIDEA. 


four  in  number,  which  is  probably  an  accidental  feature, 
three  being  the  usual  number.  The  subradials  are  gene- 
rally smaller  than  the  radial  plates  proper,  but  vary  much 
in  size  and  proportionate  form  among  themselves  ; most 
of  them  are  higher  than  wide.  The  radial  plates  are  elon- 
gate, hexagonal,  three  in  number,  except  on  one  ray  there 
are  only  two  below  the  first  bifurcation ; and  above  they 
are  small  and  many  sided,  with  inter-supraradials  between 
the  branches  of  the  ray.  The  interradial  and  anal  areas 
are  large  and  composed  of  a large  number  of  plates,  differ- 
ing much  both  in  form  and  size ; the  first  is  hexagonal,  as 
large  as  the  first  radials,  and  situated  in  the  receding 
angles  of  two  subradials  : the  entire  area  is  considerably 
protruding  beyond  the  plain  of  the  radial  series. 

Entire  surface  granulose. 

Articulating  faset  for  the  attachment  of  the  column  is 
large. 

This  specimen  is  almost  too  imperfect  for  description;  but  as  it  has  for  some 
years  been  a well  known  fossil  in  the  Collection  of  the  late  IIknry  Puatten,  and 
is  an  extremely  interesting  specimen  and  the  only  one  known  of  its  peculiar  struc- 
ture ; I have  thought  best  to  describe  it  so  far  as  its  condition  will  bear;  and  name 
it  in  honor  of  him.  ' 

Note.  It  is  possible  that  the  above  described  species  may  not  belong  to  the  genus  to  which 
we  have  referred  it;  but  what  remains  of  the  specimen  has  all  the  characters  of  the  genus 
Forbesiocrinus,  except  the  number  of  plates  in  the  basal  series. 

G-ological  posiiioti  and  locality.  In  the  Carboniferous  limestone  series,  precise 
position  not  known,  but  probably  not  below  the  Warsaw  division  ; it  was  collected 
in  Alabama,  but  the  exact  locality  is  not  given. 


BRACHIOPODA 


Oi'tliis  kaskaskieiisis  ( n.  s.). 

Shell  resupinate,  semicircular  in  outline.  Dorsal  valve 
regularly  convex,  most  gibbous  near  the  umbo;  cardinal 
extremities  slightly  elevated  or  recurved.  Ventral  valve 
generally  concave  ; beak  elevated,  and  in  some  specimens 
the  elevation  extends  back  toward  the  middle,  distorting 
the  shell.  Area  rather  low;  marked  by  fine,  closely 
arranged  transverse  strije,  which  are  most  distinct  near 
the  edges  of  the  foramen  and  becoming  obsolete  toward 
the  extremities ; extends  to  the  extremities  of  the  cardi- 
nal line,  which  is  equal  in  length  to  the  greatest  width  of 
the  shell  below.  Foramen  subtriangular,  height  greater 
than  the  width,  partially  closed,  the  cardinal  process  of 
the  dorsal  valve  filling  the  opening. 

Surface  marked  by  fine,  distinct,  rounded,  somewhat 
distorted  radiating  striae,  which  are  increased  by  implan- 
tation and  crossed  by  very  fine  undulating  striae,  which 
give  to  the  surface,  when  seen  through  a lens,  a beauti- 
fully cancellated  structure,  which  character  is  very  distinct 
on  a partially  exfoliated  surface. 

This  Orthis  belongs  to  the  group  usually  referred  to  Orlhis  umbraculum,  but 
differs  materially  from  all  the  species  of  that  group  hitherto  described.  It  differs 
from  O.  kaokiik  and  robusta  (II all)  in  being  a much  smaller  shell,  the  dorsal  valve 
being  less  convex,  and  the  ventral  valve  more  deeply’’  concave,  giving  a more  pointed 
appearance  to  the  beak  of  the  ventral  valve;  in  the  area  being  not  more  than  half 
the  height,  in  comparison  Avith  the  width  of  the  shell,  as  that  of  robusta.  The 
beak  of  this  species  is  often  flattened  and  distorted,  as  if  having  been  attached  to 
some  foreign  body  during  life.  Its  area  is  not  more  than  one  half  the  height  of  that 
of  0.  umbraculum,  according  to  the  figuresgiven  by  De  Koninck;  and  the  strim  are 
much  more  closely  arranged  in  this  species. 

Geological  position  and  localities.  This  Orthis  appears  to  be  peculiar  to  the  Kas- 
kaskia  division  of  the  Carboniferous  limestone  series,  and  is  found  at  Kas-^  skia 
and  Chester,  Illinois. 


32 


BRACIIIOPODA. 


Ortlsis  liisalkiBSES  (n.s  ). 

Shell  subquadrate,  widest  below  the  middle ; sides 
broadly  rounded  toward  the  front ; length  one  quarter  less 
than  breadth.  Dorsal  valve  depressed  convex,  and  having 
the  appearance  of  a broad  shallow  sinus  extending  from 
beak  to  base.  General  form  of  ventral  valve  flattened  or 
very  depressed  convex,  becoming  slightly  gibbous  toward 
the  hinge  line  ; beak  pointed,  and  projecting  beyond  that 
of  the  opposite  valve  ; area  low,  rapidly  sloping  from  the 
beak,  and  becoming  linear  toward  the  extremities;  fora- 
men narrow,  triangular,  higher  than  wide,  closed  except  a 
small  space  at  the  base  ; callosity  rounded.  There  is  a 
line,  which  in  some  specimens  is  quite  distinct,  crossing 
the  area  from  the  beak  to  its  base  at  a point  midway  from 
the  foramen  to  the  cardinal  extremities. 

Surface  marked  by  sharp  rugose  radiating  striae, 
increased  by  implantation,  and  crossed  by  much  finer 
concentric  striae  and  indistinct  lines  of  growth. 

Geological  posiiion  and  localities.  In  the  Upper  Coal  measures,  Lasallc,  Illinois. 

Oitlits  riidiiiioiida  ( n.  s.). 

Shell  subquadrate  ; length  and  breadth  equal ; widest 
below  the  middle.  Dorsal  valve  depressed  convex,  slightly 
flattened  in  the  middle  toward  the  front.  Ventral  valve 
less  convex  than  the  dorsal ; greatest  gibbosity  near  the 
umbo,  which  is  sometimes  flattened  by  being  attached 
during  life  to  some  foreign  body.  Area  large,  straight  or 
slightly  curved  outward,  receding  backward  from  the 
hinge  ; height  at  the  beak  about  one  fourth  its  entire 
length ; upper  margin  gradually  sloping  from  the  beak  to 
the  extremities  of  the  cardinal  line.  Foramen  narroAver 
than  high,  closed  by  a rounded  deltidium,  except  a small 
space  at  the  base  which  is  filled  by  the  cardinal  process 
of  the  dorsal  valve. 


BRACIIIOPODA. 


33 


Surface  of  both  valves  marked  by  distinct,  somewhat 
elevated,  rounded  stria?  which  are  increased  by  implanta- 
tion, the  spaces  between  them  being  a little  wider  than 
the  strijB  ; also  by  much  finer  concentric  striae  which  cross 
the  radiating  striae,  giving  them  a somewhat  rugose  tex- 
ture ; and  by  numerous  strong  imbricating  concentric  lines 
of  growth. 

This  species  differs  from  the  last  in  the  proportions  of  the  shell,  which  is  much 
more  elongated  than  that;  in  the  greater  convexity  of  the  valves;  in  the  greater 
height  of  the  area,  and  in  the  radiating  striae  being  finer  and  less  rugose  than  in 
that  species,  as  well  as  in  its  strong  imbricating  lines  of  growth  : it  is  also  a thicker 
shell,  and  the  muscular  scars  of  the  interior  of  the  valves  are  deep  and  more  dis- 
tinct; the  dental  lamella  and  central  septum  stronger.  The  central  septum  is  a 
peculiar  character  in  these  fossils. 

Geological  position  and  locality.  In  the  Coal  measures  twelve  miles  northwest  of 
Richmond,  Missouri. 


Ortliis  pratteiii  ( n.  s.). 

Shell  subquadrangular  in  outline,  somewhat  broader 
than  long  : cardinal  line  much  less  than  the  greatest  width 
of  the  shell,  which  is  about  the  middle  of  the  dorsal  valve, 
not  very  gibbous.  Dorsal  valve  very  slightly  convex,  fullest 
at  the  middle  below  the  umbo,  having  a broad  undefined 
sinus  on  the  front  of  the  shell  which  does  not  extend 
beyond  its  middle,  and  also  one  on  each  side  reaching 
from  the  beak  to  the  side  of  the  shell  between  the  cardinal 
line  and  the  widest  part  of  the  shell,  depressing  the  edge 
of  the  valves,  giving  them  when  viewed  edgewise  a some- 
what undulating  curve.  Ventral  valve  much  larger  than 
the  dorsal,  strongly  pointed  at  the  beak,  which  is  extended 
above  the  hinge  line  from  one  fourth  to  one  third  the 
whole  length  of  the  shell ; gradually  sloping  from  beak  to 
front,  without  visible  curve  except  by  distortion.  Arefi 
high,  triangular,  the  base  of  the  triangle  being  but  little 
greater  than  the  sides  : foramen  narrow,  height  four  times 
5 


34 


BRACIIIOPOUA. 


the  breadtli ; closed,  except  a small  space  at  the  base, 
which  is  filled  by  the  cardinal  process  of  the  opposite 
valve.  Surface  of  the  area  marked  by  longitudinal  striae, 
indicating  the  stages  of  growth. 

Surface  of  the  shell  marked  by  distinct,  somewhat  ele- 
vated striae  which  are  increased  by  implantation,  the 
intermediate  spaces  being  smaller  than  the  striae ; and  by 
very  fine  concentric  striae  which  give  a finely  cancellated 
appearance  to  the  surface  when  under  a lens,  as  well  as 
by  strong  somewhat  distant  imbricating  lines  of  growth. 

This  shell  is  closely  related  to  the  two  jireceding  species,  but  differs  from  both  of 
them  in  the  great  height  of  the  area  and  the  narrowness  of  the  deltidial  plate  : the 
.strim  are  not  so  distant  and  not  so  rough  as  in  either  of  them.  In  the  proportionate 
width  of  the  shell  it  resembles  Orthis  lasallensis,  but  is  easily  distinguished  by  the 
height  of  the  area,  which  in  that  species  is  very  small.  From  the  last  it  differs  in 
being  wider  than  long,  the  length  and  breadth  of  that  species  being  nearly  or  quite 
equal;  and  the  proportionate  height  of  the  area  is  also  very  different. 

Geological  position  and  locality.  In  the  Coal  measures,  Charbonier,  Missouri, 

Prodiictus  asperus  ( n.  s.). 

Shell  of  medium  size,  usually  longer  than  wide  ; hinge 
line  eqnal  to  four  fifths  the  greatest  width  of  the  shell. 
Cardinal  extremities  usually  rounded  or  obtusely  angular. 
Ventral  valve  ventricose,  moderately  recurved  and  extend- 
ing slightly  beyond  the  hinge  line  ; usually  divided  by  a 
broad  shallow  undefined  sinus  extending  from  beak  to 
base  ; front  of  the  valve  often  somewhat  flattened,  rounded 
on  the  sides  to  near  the  middle  of  the  shell,  from  which 
point  they  became  flattened,  and  fall  nearly  perpendicular 
upon  the  cardinal  line  ; auriculate  extensions  slightly  pro- 
duced and  thickly  set  with  spines.  Dorsal  valve  moderately 
concave  to  near  the  anterior  prolongment,  at  Avhich  place 
it  becomes  abruptly  deflected  with  that  of  the  ventral 
valve  ; immediately  beneath  the  beak  of  the  ventral  valve 
it  is  marked  with  a shallow  cavity,  from  which  a Ioav  unde- 
fined, someAvhat  angular  ridge  passes  obliquely  outAvard  to 


BRACIIIOPODA. 


35 


the  sides  of  the  shell;  and  in  specimens  where  the  sinus 
of  the  ventral  valve  is  distinct,  there  is  a third  ridge  pass- 
ing to  the  front  of  the  shell,  less  distinctly  defined. 

Surface  of  the  ventral  valve  marked  by  a great  number 
of  spines,  the  bases  of  which  are  elongated,  or  have  the 
shell  elevated  above  them,  giving  to  the  surface  the 
ajipearance  of  being  covered  by  irregularly  broken,  radi- 
ating striae  or  ribs ; also  by  broad,  low,  rounded,  concen- 
tric bands,  which  become  narrower  and  more  closely 
arranged  toward  the  front  of  the  shell. 

The  dorsal  valve  is  also  marked  by  concentric  bands, 
which  are  more  closely  arranged  than  those  of  the  ventral, 
and  more  thickly  set  with  spines.  The  spines  are  more 
perfectly  preserved  than  those  of  the  opposite  valve,  and 
finer,  and  usually  lay  flat  upon  the  surface,  radiating  from 
the  beak.  The  spaces  between  the  spines  are  somewhat 
dejaressed,  giving  the  surface  a punctured  appearance. 

Geological  position  and  localities.  In  the  Coal  measures  at  Lasalle,  Springfield, 
and  various  other  places  in  Illinois. 


Productus  syiHinetricus  ( n.  s.). 

Shell  of  medium  size,  depressed,  suborbicular ; length 
and  breadth  about  equal.  Cardinal  line  considerably  less 
than  the  greatest  width  of  the  shell  below;  extremities 
rounded  ; auriculate  extensions  small,  but  distinct  from 
the  vault  of  the  shell,  straight  or  slightly  elevated.  Ven- 
tral valve  quite  regularly  convex,  expanding  at  the  front, 
and  entirely  destitute  of  a mesial  sinus;  front  regularly 
and  broadly  rounded ; beak  large,  little  incurved,  barely 
passing  beyond  the  hinge  line.  Dorsal  valve  regularly  con- 
cave, of  moderate  depth. 

Surface  marked  much  as  in  the  preceding  species ; but 
the  spines  and  broken  rib-like  striae  of  the  ventral  valve 
are  much  finer  and  more  thickly  set,  and  the.  concentric 


36 


BRACIIIOPODA. 


bands  are  narrower  and  more  closely  arranged,  becoming 
crowded  on  the  front  of  the  shell. 

This  shell,  though  closely  related  to  the  last  described  species,  differs  from  it  in 
being  a larger  shell,  less  ventricose  and  always  much  broader,  entirely  destitute  of 
mesial  sinus,  less  enrolled,  beak  not  projecting  so  far  beyond  the  hinge  line;  in  its 
dorsal  valve  being  less  concave,  and  nearly  or  quite  destitute  of  the  lateral  ridges 
which  pass  obliquel}’’  from  the  beak  to  the  sides  of  the  valves  in  that  species. 

Geological  position  and  localities.  In  the  Upper  Coal  measure  limestone  at 
Lasalle  and  Springfield,  Illinois. 


Pi’oductiis  Avillieramis  (n.  s.). 

Shell  above  medium  size,  subquadrate  in  general  form, 
somewhat  longer  than  wide,  greatest  width  below  the 
middle  of  the  shell ; hinge  line  entirely  straight ; cardinal 
extremities  slightly  rounded.  Ventral  valve  regularly 
arched  from  near  the  beak  to  the  base  of  the  shell,  having 
a broad,  shallow,  not  well  defined  sinus  extending  from 
beak  to  base  ; front  broadly  rounded  to  the  sides  of  the 
valve,  gradually  rounded  from  the  edges  of  the  sinus  to 
the  sides  of  the  shell  : beak  small,  pointed,  projecting 
slightly  beyond  the  cardinal  line.  Dorsal  valve  flat  over 
the  visceral  portion,  and  moderately  deflected  in  front.  A 
small  depressed  pit  exists  beneath  the  beak,  from  which 
faintly  defined  ridges  extend,  one  on  each  side  to  the  outer 
edge  of  the  valve  just  below,  and  slightly  diverging  from 
the  cardinal  line,  and  another  to  the  front  of  the  shell 
corresponding  to  the  mesial  sinus  of  the  ventral  valve. 

Surface  of  the  ventral  valve  marked  by  coarse,  much 
broken,  radiating  striae  or  ribs ; and  by  broad  concentric 
bands,  the  surface  of  which  are  somewhat  thickly  set  with 
strong  tubular  spines,  which  are  not  usually  preserved, 
their  bases  only  remaining.  The  spines  are  implanted  on 
the  ribs,  adding  much  to  their  broken  appearance.  The 
surface  structure  of  the  dorsal  valve  is  of  a somewhat  finer 
texture  than  that  of  the  other.  The  spines  are  smaller,  the 
ribs  finer,  and  the  concentric  bands  more  closely  arranged. 


BRACIIIOPODA. 


37 


The  interior  of  both  valves,  in  addition  to  the  above  char- 
acters, is  covered  by  very  fine  undulating  concentric  striae 
crossing  the  radiating  ribs. 

This  species  has  usually  been  referred  to  P.  scabriculus  (JIartin);  but  com- 
pared with  the  figures  of  that  species  given  by  I)e  Koxinck,  it  is  not  so  rectaisgu- 
lar,  being  considerably  broadest  near  the  base,  and  the  cardinal  line  being  not  more 
than  two  thirds  the  greatest  width  of  the  shell.  The  sides  of  the  ventral  valve  of 
P.  scabriculus  are  nearly  perpendicular  to  the  plane  of  the  dorsal  valve,  while  in 
this  species  they  are  regularly  rounded  from  the  edge  of  the  sinus  to  the  lateral 
borders.  The  longitudinal  ribs  are  more  broken  and  less  continuous  than  in  that 
species,  and  the  spines  are  much  more  numerous  and  not  regularly  disposed.  'J’rans- 
verse  bands  are  a feature  not  possessed,  or  at  most  very  indistinctly  so,  by  P. 
scabriculus,  while  in  this  they  constitute  a marked  character.  This  shell  has  also 
some  resemblance  to  P.  asperus,  herein  described,  but  is  a much  larger  shell, 
less  conve.x,  less  enrolled,  hinge  line  entirely  straight,  cardinal  extremities  not 
rounded  as  in  that,  mesial  sinus  more  distinct  and  the  transverse  bands  much 
larger. 

Geological  position  and  locality.  In  the  Coal  measures,  Charbonier,  Missouri. 


Proliiictus  tulm1o8{)iiiii8  ( n.  s.). 

Shell  large,  semiovate,  longer  than  wide,  gradually 
expanding  from  the  beak  to  near  the  front  of  the  shell ; 
front  rounded.  Ventral  valve  gibbous,  highly  arcuate,  hav- 
ing a shallow  well  defined  sinus  extending  from  near  the 
beak  to  the  base,  and  in  some  specimens  is  somewhat  angu- 
lar ; cardinal  line  shorter  than  the  width  of  the  shell  below ; 
extremities  rounded  or  obtusely  angular ; auricular  expan- 
sions short,  but  distinct  from  the  vault  of  the  shell.  Dorsal 
valve  concave,  and  having  a broad  low  angular  ridge  ex- 
tending from  the  cavity  beneath  the  beak  to  the  front  of 
the  shell. 

Surface  marked  by  distinct,  rounded,  somewhat  closely 
arranged  concentric  bands  which  are  covered  with  pustules 
or  spine  bases,  the  spines  themselves  being  rarely  pre- 
served ; but  when  they  are  seen,  they  are  very  fine,  and 
of  considerable  length,  one  of  our  specimens  having  them 
preserved  to  nearly  one  half  inch  in  length.  These  spines, 
when  broken,  exhibit  a tubular  structure. 


38 


BRACniOPODA. 


Specimens  of  this  species,  when  exfoliated,  usually, 
instead  of  the  pustules  or  spine  bases,  show  a deeply  and 
beautifully  punctured  surface. 

Tliis  -p  <ies  has,  in  this  country,  usually  been  reP-rred  to  P.  punctatus  (Mar- 
Tri>i),  hut  possesses  several  reinaikahle  differences,  which  have  induced  me  to  re- 
gard it  as  a distinct  species.  Taking  Dk  Koninck’s  figures  and  de.scriptions  for  the 
characters  of  tiuit  sj)coies,  our  shell  is  much  more  elongated  than  that,  being  longer 
than  wide,  while  that  is  wider  than  long.  The  auricular  extensions  arc  much  less 
l)roduced  or  flattened  than  in  that;  the  shell  expands  gradually  from  beak  to  near 
the  base,  while  that  widens  abruptly  and  is  much  more  flattened  on  the  top.  De 
Konin'cic,  in  his  description,  states  that  the  spine  bases  on  their  shell  are  arranged 
on  the  anterior  margin  of  the  bands;  while  in  this  shell  they  are  scattered  promis- 
cuously over  their  surface.  The  hinge  line  is  proportionately  much  shorter  than  in 
Martin’s  species,  and  the  heak  more  incurved.  Compared  with  P.  vittatus 
(II.ALi.’s  Geo.  Report  of  Iowa,  page  037),  it  is  more  elongated;  hinge  line  propor- 
tionately shorter;  beak  less-elevated,  and  not  so  abruptly  recurved. 

G ologicul  position  and  localitips.  In  the  Coal  measures  throughout  the  Western 
States. 


FriMlllCtUS  fiJSCk'lllutUS  ( n.  s.). 

Shell  rather  below  medium  size,  elongated;  length  of 
the  hinge  line  three-fourths  the  greatest  width  of  the  shell, 
and  auriculate.  Ventral  valve  strongly  arcuate,  flattened 
on  the  top,  or  marked  by  a broad  shallow  sinus;  sides 
nearly  perpendicular,  which,  together  with  the  flattened 
top,  gives  it  a somewhat  angnlar  appearance;  auricles  re- 
curved, pointed,  with  the  sides  of  the  shell  just  in  front  of 
them  somewhat  contracted  ; beak  small,  jfointed,  slightly 
projecting  beyond  the  hinge  line.  Dorsal  valve  profoundly 
concave,  slightly  flattened  over  the  visceral  area,  and  pro- 
longed in  front  and  at  the  sides  with  the  ventral  valve,  and 
recurved  at  the  cardinal  extremities  or  auricles. 

Surface  of  the  ventral  valve  marked  by  medium-sized 
rounded  radiating  ribs  which  are  increased  by  bifurcation, 
and  toward  the  front  of  the  shell  several  of  them  unite  in 
fascicles,  which  are  not  developed  except  in  adult  indi- 
viduals, and  are  not  seen  when  the  prolonged  portion  of 
the  valve  is  broken  away.  The  surface  is  also  marked  by 


BRACniOPODA. 


39 


very  fine  concentric  striae  and  a few  faint  wrinkles  of 
growth  on  the  upper  part  of  the  shell,  and  traces  of  spine 
bases  very  sparingly  scattered  over  the  surface,  except  on 
the  sides  immediately  over  the  ears,  where  there  is  a clus- 
ter of  eight  or  ten.  The  cavity  of  the  dorsal  valve  is  also 
marked  by  radiating  ribs,  finer  than  those  of  the  ventral 
valve,  and  frequently  bifurcating,  giving  them  a somewhat 
contorted  ajipearance.  The  concentric  wrinkles  of  this 
valve  are  more  distinct  than  those  of  the  other  valve  near 
the  cardinal  lines,  sometimes  of  equal  strength  with  tlie 
radiating  ribs,  and  bending  over  upon  the  reflected  portion 
of  the  valve  which  forms  the  auricles. 

Specimens  of  this  species  are  usually  found  with  the 
prolonged  portion  of  the  valves  broken  away,  entirely 
changing  the  appearance  of  the  shell  from  that  presented 
by  perfect  individuals. 

The  animal  appears  to  throw  a partition  across  from  the 
dorsal  to  the  ventral  valve,  which  appears,  when  the  pro- 
longment  is  broken  away,  to  be  the  continuation  of  the 
flattened  portion  of  the  valve  over  the  visceral  portion, 
and  nearly  conforming  to  its  concavity,  though  destitute 
of  its  distinct  ribs,  the  visceral  portion  being  distinctly 
limited  by  an  imbricated  ridge. 

This  species  has  usually  been  referred  to  P.  flexistria  of  M‘Cor,  from  which  it 
differs  in  being  much  less  inflated  over  the  ears  and  toward  the  beak,  and  in  the 
striae  uniting  into  fascicles  toward  the  front.  It  is  more  nearly  related  to  P.  elegans 
(N.  and  P.,  Journal  Acad.  Nat.  Sciences  of  Philadelphia,  Aug.  1854),  than  to  the 
last  mentioned  species;  but  is  a much  broader  shell,  is  frequently  marked  by  a dis- 
tinct mesial  sinus;  more  extended  on  the  hinge  line,  much  less  marked  by  tubercles, 
and  having  the  fasciculate  striae  on  ihe  front  of  the  ventral  valve. 

Geological  position  and  localities.  In  the  Kaskaskia  division  of  the  Carboniferous 
limestone  series,  at  Fountain  Bluff,  Kaskaskia  and  Chester,  Illinois,  and  Leven- 
worth,  Indiana. 


40 


BRACHIOPODA, 


Pl  iMlllCtllS  illfhltllS  ( n.  s.). 

Shell  of  medium  size,  extremely  gibbous  or  inflated  and 
strongly  enrolled  ; cardinal  line  straight,  equal  to  or  greater 
than  the  greatest  width  of  the  shell;  broadly  rounded  in 
front.  Ventral  valve  extremely  gibbous,  geniculated  above 
the  middle,  divided  by  a strong,  well  defined,  rounded  sinus 
extending  from  near  the  beak  to  the  base;  beak  large, 
rounded,  and  projecting  a little  beyond  the  hinge  line ; 
auricular  extension  somewhat  inflated,  divided  from  the 
vault  of  the  shell  by  a distinct  depression  extending  from 
near  the  beak  to  the  sides  of  the  shell  at  a point  back  of 
the  middle.  Dorsal  valve  unknown. 

Surface  marked  by  regular,  somewhat  indistinctly  round- 
ed longitudinal  ribs,  increased  by  bifurcation,  and,  behind 
the  geniculation  of  the  shell,  by  closely  arranged  concen- 
tric bands  or  wrinkles ; the  entire  surface  being  marked  by 
very  fine,  slightly  undulating,  concentric  striae,  visible  only 
by  the  use  of  a magnifier;  also  a few  faint  traces  of  spine 
bases  are  distributed  over  the  surface  and  on  the  ears. 

Tliis  species  has  some  resemblance  to  P.  splendens  (N.  and  P.,  Journal  Acad. 
Nat.  Sciences,  Philadelphia,  1854),  but  is  more  inflated,  much  more  elongated,  less 
extended  on  the  hinge  line,  strise  finer,  spine  bases  less  numerous,  beak  and  umbo 
less  flattened,  finer  ribs,  and  depressed  between  the  vault  of  the  shell  and  the 
auricles. 

GMlogical  position  and  locality.  Carboniferous  limestone,  Levenworth,  Indiana. 

Productiis  pileifontiis  ( n.  s.). 

Shell  of  medium  size,  slender,  gradually  expanding  from 
beak  to  base,  very  strongly  enrolled  and  entirely  desti- 
tute of  mesial  sinus.  Ventral  valve  strongly  arcuate,  very 
gibbous,  much  produced  in  front  and  inflated  at  the  sides; 
cardinal  line  very  short ; beak  small,  pointed  and  incurved. 
Dorsal  valve  small,  profoundly  concave,  and  produced  in 
front  and  on  the  sides  with  the  opposite  valve. 

Surface  marked  by  numerous  fine  even  thread-like  radia- 
ting striae,  increased  by  implantation  and  often  distorted 


BRACIIIOPODA. 


41 


slightly,  and  by  transverse  wrinkles  Avhich  are  strong  on 
the  sides  of  the  valve  but  scarcely  perceptible  on  the  mid- 
dle, except  on  the  dorsal  valve  where  they  pass  entirely 
over ; body  of  the  ventral  valve  also  marked  by  a few 
spine  bases. 

Thii^pecies  bears  considerable  resemblance  to  P.cora  (D’Orbignt);  but  differs 
from  it,  when  compared  with  specimens  from  the  same  localities  as  those  mentioned 
by  him,  in  being  a much  more  attenuated  shell,  in  having  a much  smaller  and  more 
pointed  beak,  shorter  hinge  line,  more  contracted  at  the  edges  of  the  ventral  valve: 
also  more  regularly  arched  from  beak  to  base;  that  species  having  a broad  depressed 
beak,  being  a broader  shell,  and  regularly  curved  to  a little  in  front  of  the  umbo  or 
near  the  middle  of  the  shell;  then  produced  in  a right  line  to  near  the  front  of  the 
shell,  which  is  often  expanded.* 

Geological  position  and  locality.  In  the  Kaskaskia  division  of  the  Carboniferous 
limestone,  Chester,  Illinois. 

Asilbocelia  ^emimila  ( n.  s.). 

Shell  minute  ; length  and  breadth  nearly  equal.  Ven- 
tral valve  extremely  gibbous  and  arcuate,  having  a slight 
depres_sed  sinus  extending  from  beak  to  base ; sides  and 
front  rounded ; beak  comparatively  large,  strongly  incurv- 
ed, projecting  considerably  above  the  hinge  line  ; cardinal 
area  small,  proportionately  high,  triangular,  much  shorter 
than  the  width  of  the  shell  below;  extremities  rounded  : 
deltidium  high  triangular,  extending  nearly  to  the  point 
of  the  beak;  width  at  the  base  about  one-third  the  entire 
length  of  the  cardinal  line.  Dorsal  valve  very  much 
smaller  than  the  opposite  one,  sub-semicircular ; length 
very  little  more  than  the  width,  flat  or  slightly  convex, 
most  gibbous  at  the  beak  ; hinge  line  straight. 

Surface  apparently  smooth. 

This  species  is  very  closely  allied  to  Orthis  umbonata  of  Conrad,  but  differs  from 
it  in  having  the  hinge  line  less  than  the  width  of  the  .shell  below,  and  also  in  the 
ventral  valve  being  less  gibbous,  and  the  beak  not  so  much  incurved. 

Geological  position  and  localities.  In  the  Coal  measure  slates  and  shales  of 
Peoria  and  Bureau  counties,  Illinois. 

• The  above  comparisons  are  made  with  American  specimens,  for  the  reason  that  D'Orbignt’s 
original  specimens  were  from  this  country,  while  those  figured  by  De  Koninck  in  his  monograph 
are  European  specimens  identified  by  D’Orbignv’s  description. 

6 


42 


BRACHIOPODA. 


Spirifer  transversa  ( n.  s.)- 

Shell  small,  varying  from  sub-semicircular  to  subtrian- 
gular,  gibbous;  valves  nearly  equal;  diameter  equal  to  the 
length  of  the  shell ; cardinal  extremities  produced  in  mu- 
cronate  points.  Ventral  valve  slightly  the  most  gibbous; 
mesial  sinus  deep  and  subangular,  extending  from  beak  to 
base,  narrow  and  having  a small  plication  in  the  bottom ; 
beak  slightly  incurved  over  the  area,  which  is  of  medium 
height,  and  reaches  to  the  extremity  of  the  cardinal  line  ; 
foramen  triangular,  higher  than  wide,  having  a distinct 
groove  down  each  side  for  the  insertion  of  the  deltidial 
plate.  Dorsal  valve  most  gibbous  near  the  beak,  from  which 
point  it  curves  gently  toward  the  front  of  the  shell ; mesial 
elevation  of  moderate  height,  narrow  and  having  a de- 
pressed line  along  the  centre,  corresponding  to  the  eleva- 
tion in  the  bottom  of  the  sinus  in  the  opposite  valve. 

Surface  marked  by  nine  to  twelve  strong,  somewhat 
angular  plications  on  each  side  of  the  mesial  fold  and  sinus, 
crossed  by  fine  sharp  closely  arranged  concentric  striae, 
arching  abruptly  up  or  back,  both  on  the  plications  and 
mesial  fold.  The  surface  of  the  cardinal  area,  and  the  por- 
tion of  the  shell  bounding  it,  is  covered  by  fine  but  clearly 
distinct  granules. 

This  species  belongs  to  the  group  of  which  S.  mucronatus  of  the  Hamilton  rocks 
of  New-York  may  be  considered  the  type;  from  which  species  it  differs  in  being  a 
much  smaller  shell,  much  more  ventricose,  having  much  more  closely  arranged  con- 
centric lines,  and  in  having  more  distinct  plications,  which  are  not  directed  toward 
the  beak  as  in  that  shell.  It  differs  from  S.  submucronatus  of  Hall  (Geo.  of  Iowa, 
PI.  4,  fig.  4),  in  being  a shorter  shell,  and  in  the  form  of  the  mesial  elevation,  which 
in  that  species  is  single  and  much  broader  than  in  this;  in  having  a less  number  of 
plications,  area  not  so  high,  and  more  gradually  sloped  from  the  beak  toward  the 
cardinal  line,  instead  of  carrying  its  breadth  for  some  distance,  then  terminating 
abruptly  as  in  his  fig.  46.  This  is  also  a much  more  rotund  species  than  any  spe- 
cimens of  that.  It  differs  from  S.  kentuckensis  of  Shumard,  in  having  a greater 
number  of  plications,  which  arc,  proportionately  to  the  size  of  the  shell,  much  more 
slender  and  more  closely  arranged ; and  the  mesial  fold  of  that  species  has  no  cen- 
tral depression,  nor  the  sinus  an  elevation. 

Geological  position  and  locality.  In  the  Kaskaskia  division  of  the  Carboniferous 
limestone  at  Buzzard’s  Roost,  Alabama. 


BRACHIOPODA. 


43 


Spirifer  siibelliptica  (n.  s.)- 

Shell  transversely  subelliptical,  gibbous ; hinge  line 
less  than  the  greatest  width  of  the  shell ; cardinal  extre- 
mities regularly  and  strongly  rounded  ; beaks  distant  and 
slightly  incurved.  Mesial  sinus  of  the  ventral  valve  broad 
and  shallow,  not  angular,  somewhat  broadly  expanded 
toward  the  front  of  the  shell ; area  moderately  high, 
rapidly  sloping  from  the  beak  downward,  and  not  reach- 
ing the  extremities  of  the  cardinal  line  ; foramen  narrow, 
height  double  the  width,  distinctly  grooved  at  the  sides. 
Dorsal  valve  less  gibbous  than  the  ventral ; mesial  eleva- 
tion broadly  rounded  and  simple. 

Surface  marked  by  from  five  to  seven  simj)le  rounded 
plications,  which  are  distinct  on  the  front  of  the  shell,  but 
gradually  die  out  as  they  approach  the  cardinal  line,  and 
crossed  by  fine  closely  arranged  concentric  lamellae  which 
arch  abruptly  upward  as  they  cross  the  plications  and 
mesial  fold.  The  lower  edges  of  the  lamellae  are  orna- 
mented by  very  fine  closely  arranged  hair-like  spine  bases. 

This  differs  from  the  foregoing  species  by  being  a larger  shell,  much  less  rotund 
and  much  longer  in  proportion  to  i s width,  and  in  its  simple  mesial  fold  and  sinus, 
as  well  as  in  other  respects.  It  differs  from  S.  kentuckensis  in  being  a much  larger 
shell,  i»  its  hinge  line  being  less  than  the  greatest  width  of  the  shell,  and  its  cardi- 
nal extremities  rounded.  Specimens  of  this  species  are  usually  found  flattened,  from 
which  we  infer  that  the  substance  of  the  shell  is  very  thin. 

Geological  position  and  locality.  In  the  Kaskaskia  division  of  the  Carboniferous 
limestone,  Buttonmould  Knob,  Kentucky. 


Spirifer  perplexa  ( n.  s.). 

Shell  small,  varying  in  form  from  suborbicular  to  trans- 
versely subelliptical,  globose ; widest  in  the  centre,  and 
having  the  cardinal  extremities  strongly  rounded.  Ventral 
valve  much  the  largest,  convex,  most  gibbous  near  the 
beak,  destitute  of  sinus  (except  a faint  depressed  line  in 
rare  instances) ; beak  prominent,  and  strongly  recurved 
over  the  area ; hinge  line  much  less  than  the  greatest 


'44 


BRACIIIOPODA. 


width  of  the  shell ; area  triangular,  little  wider  than  high, 
not  well  defined  ; triangular  foramen  comparatively  large, 
higher  than  wide,  occupying  nearly  one  half  the  entire 
length  of  the  area.  Dorsal  valve  generally  depressed  con- 
vex, sometimes  quite  gibbous,  and  most  so  near  the  beak, 
which  is  slightly  incurved  ; transversely  elliptical,  with 
the  upjier  side  of  the  ellipse  flattened. 

Surface  marked  by  numerous  fine  closely  arranged  con- 
centric bands,  the  lower  margin  of  which  sometimes 
shows  a very  fine  fimbriate  structure,  giving,  when  well 
preserved,  the  appearance  of  fine  radiating  strim  which 
can  only  be  seen  with  a magnifier. 

This  species  is  one  of  the  group  usually  referred  to  S.  lineatus  of  Martin;  but 
according  to  their  figures,  it  is  a very  distinct  shell.  The  difference  of  size  in  adult 
individuals  is  alone  of  specific  importance.  Our  shell  seldom  attains  a breadth  of 
more  than  five  eighths  of  an  inch,  while  theirs  is  sometimes  two  inches;  the  lamella 
of  S.  lineatus  is  also  much  more  conspicuous,  giving  a more  rugose  surface  than  in 
this  species. 

Geological  position  and  locality.  In  the  Upper  Coal  measures  in  almost  every 
part  of  the  country  where  rocks  of  that  age  exist. 


^pirifer  su!>\ eiitiicosa  (n.  s.). 

Shell  of  medium  size,  transverse,  subelliptical,  width 
one  fourth  greater  than  the  length ; cardinal  line  slightly 
less  than  the  greatest  Avidth  of  the  shell  below ; extremi- 
ties rounded ; valves  about  equal,  and  regularly  rounded 
in  front  and  on  the  sides.  Ventral  Amlve  gibbous  and  regu- 
larly arcuate,  having  a shallow,  well  defined,  regularly 
rounded  sinus  extending  from  beak  to  base  ; beak  small, 
incur\md ; area  low,  extending  to  the  extremities  of  the 
cardinal  line,  coarsely  striated  transversely,  edges  or 
boundary  rounded.  Dorsal  valve  of  equal  thickness  with 
the  other,  but  more  angular  in  its  convexity,  elevated  in 
the  centre  into  a prominent  mesial  ridge  Avhich  is  sharply 
angular  in  the  middle  ; beak  rather  large,  gibbous,  and 
someAvhat  incurved. 


BRACHIOPODA. 


45 


Surface  of  each  valve  marked  by  from  sixteen  to  twenty 
low  rounded  plications  on  each  side  of  the  mesial  fold  and 
sinus,  and  from  seven  to  nine  on  the  mesial  fold.  Some  of 
the  plications  bifurcate,  while  others  are  simple  on  the 
same  specimen.  Also  marked  by  fine  concentric  strim, 
which  slightly  undulate  as  they  cross  the  plications. 

This  shell  is  closely  allied  to  S.  ivcrebescens  of  Hall  (Geo.  Rep.  Iowa,  PI.  27, 
fig.  6),  but  differs  considerably  in  detail.  The  length  of  the  hinge  line  is  less  than 
the  width  of  the  shell  below;  extremities  rounded;  plications  often  bifurcating.  In 
that  species  the  length  of  the  hinge  fine  is  equal  to  or  greater  than  the  width  of  the 
shell  below;  extremities  salient  or  submucronate;  plications  stronger,  and  usually 
simple;  mesial  prominence  less  elevated,  less  angular,  and  po.sscssing  a less  number 
of  plications. 

Geological  position  and  locality.  In  Coal  measures.  Big  Creek,  Indiana;  near 
New-llarmony. 


Rofzia  (n.  s.). 

Shell  small,  subglobose,  length  and  breadth  equal.  Ven- 
tral valve  regularly  arched  from  beak  to  base  ; scarcely 
sinuate  except  by  the  smaller  size  of  the  two  central  plica- 
tions ; beak  small,  projecting  considerably  beyond  that  of 
the  opposite  valve,  slightly  incurved,  truncated  by  a small 
rounded  foramen;  cardinal  area  very  small,  triangular,  the 
base  little  more  than  one  fifth  the  Avidth  of  the  shell,  dis- 
tinctly defined,  longitudinally  striate ; deltidium  compara- 
tively large,  Avith  the  sides  subparallel:  the  centre  is 
depressed,  giving  it  a bilobed  appearance,  base  more  than 
one-third  the  width  of  the  cardinal  line,  Avhile  the  upper 
end  is  the  full  breadth  of  the  foramen.  Dorsal  valve  more 
convex  than  the  ventral,  fullest  near  the  beak. 

Surface  marked  by  from  nine  to  sixteen  simple  sharply 
rounded  plications,  Avhich  extend  from  beak  to  base : the 
two  outermost  on  each  side  are  rather  indistinct;  the  tAvo 
central  ones  on  the  ventral  valve,  and  one  on  the  dorsal, 
are  somewhat  finer  than  the  others,  which  feature  gives 
the  shell  the  appearance  of  being  slightly  sinuous  on  each 
valve.  Shell  structure  highly  punctate  under  a strong  lens. 


64 


BRACHIOPODA. 


This  species  more  closely  resembles  R.  punctulifera  of  Shumard  (Trans.  Acad. 
Sci.  St.  Louis,  Vol.  I,  No.  2),  but  is  a smaller  shell,  not  so  much  elongated,  more 
globose,  has  normally  a less  number  of  plications  and  proportionately  a smaller 
area. 

His  species  is  described  as  having  a moderately  wide  shallow  sinus  extending  from 
the  front  nearly  to  the  beak;  a feature  not  possessed  by  this  shell,  there  being  no 
proper  sinus,  and  only  the  appearance  of  one  near  the  front. 

Geological  position  and  localities.  In  limestone  of  the  Upper  Coal  measures  in 
Menard,  Mason,  Fulton,  Peoria,  Tazewell,  Knox,  Marshall,  and  many  other  coun- 
ties in  Illinois. 


Atlijriis  si)iriferoides  ( n.  s.). 

Shell  transversely  serai-elliptical ; hinge  line  straight ; 
width  double  the  length.  Dorsal  valve  gibbous,  having  a 
strong  double  mesial  elevation  which  extends  from  beatc  to 
base;  beak  incurved.  Ventral  valve  most  gibbous  toward 
the  beak ; mesial  sinus  deep,  slightly  emarginate  in  front, 
corresponding  to  the  depression  in  the  mesial  elevation  of 
the  opposite  valve  ; beak  closely  incurved  over  that  of  the 
opposite  valve  ; foramen  very  broad,  and  entirely  filled  by 
the  beak  of  the  opposite  valve.  Both  valves  thickened  on 
the  cardinal  line,  giving  it  almost  the  appearance  of  a 
linear  area. 

Surface  traversed  by  somewhat  closely  arranged  trans- 
verse lamellose  bands,  indicating  the  stages  of  growth,  and 
slightly  arching  upward  on  the  mesial  fold  and  sinus  ; and 
also  by  very  fine  intermediate  strim,  and,  in  well  pre- 
served specimens,  it  also  exhibits  fine  radiating  strise. 

This  species  is  closely  allied  to  Af.  phalaena  of  Phillips,  which  is  the  only  species 
of  this  form  I know  of  having  been  described;  but  is,  proportionately  with  the 
length  of  the  shell,  much  less  extended  on  the  hinge  line;  the  concentric  lamellae 
are  more  distant,  and  the  mesial  sinus  more  profound.  It  differs  from  any  species 
of  this  group  hitherto  described  from  our  rocks,  in  its  strong  resemblance  to  speci- 
mens of  the  Genus  Spirifer. 

Geological  position  and  locality.  In  Kaskaskia  division  of  the  Carboniferous 
limestone  series.  Fountain  Bluff,  Illinois. 


BRACHIOPODA. 


47 


Atliyrus  orbicularis  (n.  s.)- 

Shell  sub-circular,  or  varying  from  transversely  sub- 
elliptical to  subovately  elongate,  moderately  gibbous.  Dor- 
sal valve  less  than  the  ventral,  depressed  convex,  rarely 
slightly  elevated  in  front;  beak  closing  the  foramen  of  the 
opposite  valve.  Ventral  valve  convex,  strongly  gibbous 
toward  the  beak;  front  sometimes  flattened,  but  without 
true  sinus ; beak  prominent,  slightly  incurved,  and  ver- 
tically or  somewhat  obliquely  truncated  by  a circular 
foramen. 

Surface  distinctly  marked  by  concentric  lamellose  bands 
of  growth. 

This  species  is  closely  allied  to  A.  sublamcllosa  of  Hall  (Geo.  Kept.  Iowa,  p.  702), 
from  which  it  is  easily  distinguished  by  having  a larger  ventral  than  dorsal  valve, 
while  in  that  the  dorsal  valve  is  much  the  largest;  and  by  the  much  greater  eleva- 
tion or  thickening  of  the  ventral  valve  toward  the  beak. 

It  has  sometimes  been  referred  to  Tercbratula  plano-sulcata  of  Phillips,  from 
which  it  differs  in  being  a less  rotund  shell,  and  in  the  much  less  gibbosity  or  infla- 
tion of  its  ventral  valve  toward  the  front  of  the  shell,  as  well  as  in  other  respects. 

Geological  position  and  localities.  In  Coal  measures,  particularly  the  upper  por- 
tion, extensively  distributed  in  the  Western  States. 

Atliyrus  differeiitiiis  ( n.  s.). 

Shell  varying  in  form  from  subcircular  to  subelliptical, 
and  sometimes  subquadrate ; greatest  width  about  the 
middle.  Dorsal  valve  quite  regularly  convex,  slightly  ele- 
vated in  front  into  a broad  mesial  prominence ; beak 
incurved  beneath  that  of  the  opposite  valve,  and  partially 
closing  the  foramen.  Ventral  valve  more  gibbous  than  the 
dorsal,  having  a narrow  and  generally  well  defined  sinus 
extending  from  near  the  beak  to  the  base,  widening  more 
or  less  in  different  specimens  as  it  approaches  the  front 
of  the  shell,  though  usually  well  defined  along  its  centre 
by  a somewhat  sharply  rounded  depression,  and  inflated 
along  the  sides  ; front  is  produced  ; beak  slightly  incurved, 
and  truncated  vertically  by  a round  foramen  of  medium 


size. 


V 


48  BRACmOPODA. 

Surface  marked  by  fine  concentric  stricc,  and  also  by 
stronger  lamelliB  marking  the  stages  of  growth.  Partially 
exfoliated  specimens  sometimes  show  radiating  striae, 
Avhich  are  not  visible  on  perfect  shells. 

This  species  differs  fi  oin  yithyrus  su'>quadruta  of  IIai.i.  (Geo.  Rep.  Iowa,  PI.  27, 
fig.  2),  in  the  more  regular  convexity  of  its  valves,  in  the  elevated  front  being 
broader  and  lower.  The  ventral  valve  of  yJ.  sabquadrata  is  nearly  straight  from  the 
centre  of  the  shell  to  the  outer  edge  of  the  mesial  sinus,  while  that  of  this  species 
is  regularly  convex.  It  differs  from  Terrehratala  suhtillta  o(  Hall  in  being  much 
wider  proportionately  to  its  length,  in  its  more  circular  out  ine,  and  in  its  sinus 
being  more  distinctly  defined  much  nearer  the  beak,  and  more  sharply  defined 
along  its  centre  on  the  front  half  of  the  shell. 

This  is  one  of  our  American  forms  which  has  been  referred  to  Terebratula 
royssii  (Leveii.le);  but  according  to  De  Koninck’s  descriptions  and  figures,  it 
possesses  differences  which  are  clearly  of  specific  importance.  He  states  in  his  de- 
scription that  the  principal  character  of  T.  royssii  consists  in  a sort  of  epidermis 
composed  of  a great  number  of  thin,  narrow,  concentric  lamellge,  formed  by  the 
union  of  a great  number  of  small  spines  implanted  upon  the  outer  edge  of  the  con- 
centric lines  of  growth,  a character  never  possessed  by  specimens  of  our  shell.  The 
sinus  of  the  European  specimens  is  broader,  more  profound,  and  becomes  obsolete 
near  the  middle  of  the  shell,  and  is  regularly  concave  : in  this  it  extends  to  near 
the  beak,  and  is  abruptly  rounded  (approaching  an  angle)  at  the  bottom,  and  usu- 
ally somewhat  inflated  at  the  sides. 

Geological  position  and  localities.  In  Coal  measures  at  Lasalle,  Springfield, 
Belleville,  and  Sparta  (Illinois),  and  near  Richmond  and  at  Charbonier  (Missouri). 


Terebratula  iuoruata  (n  s.). 

Shell  elongate,  ovate,  length  once  and  a half  the 
breadth,  widest  below  the  middle,  front  rounded.  Ventral 
valve  but  slightly  convex,  fullest  near  the  beak,  flattened 
or  slightly  concave  in  front ; beak  large,  projecting  con- 
siderably beyond  that  of  the  dorsal  valve,  and  incurved; 
size  and  form  of  the  foramen  indeterminable  from  the 
broken  condition  of  the  specimens  : sides  of  the  valve 
near  the  beak  abruptly  inflected  to  meet  those  of  the  oppo- 
site one.  Dorsal  valve  more  gibbous  than  the  other,  very 
convex  near  the  beak,  spreading  toward  the  sides  and 
front,  with  the  centre  sharply  rounded. 

Surface  marked  by  a few  distant  lines  of  growth  some- 


BRACHIOPODA. 


49 


what  elevated,  by  fine  concentric  striae,  and  is  finely  but 

closely  and  beautifully  punctate. 

Geological  position  and  locality.  In  Coal  measure  limestones  in  Sangaman  county, 
Illinois.  It  is  also  found  in  the  Carboniferous  limestone  series  as  low  down  as  the 
Keokuk  division. 


RliyiichoiielLi  eatonisetbrmis  ( n.s.). 

Shell  very  gibbous,  subtriangular ; greatest  width  near 
the  front,  which  is  truncate  ; sides  regularly  rounded  to 
near  the  beak,  which  is  small  and  slightly  protruded  be- 
yond the  curve  ; valves  unequal.  Ventral  valve  convex 
near  the  beak  and  at  the  sides,  having  the  centre  depressed 
into  a very  profound  rounded  sinus,  which  is  almost  as 
broad  as  the  greatest  width  of  the  valve,  and  prolonged  in 
front  into  a linguliform  extension  which  conforms  to  the 
elevated  front  of  the  opposite  valve ; beak  slightly  in- 
curved over  that  of  the  opposite  one.  Dorsal  valve  pro- 
foundly gibbous  and  highly  elevated  in  front,  regularly 
arched  from  beak  to  base,  and  rapidly  sloping  from  the 
edge  of  the  elevation  to  the  sides  of  the  shell ; slope 
nearly  straight  at  the  front  of  the  shell,  and  convex  toward 
the  middle.  The  mesial  and  front  elevations  are  marked 
by  from  three  to  five  strong  angular  plications,  while  the 
remaining  portion  of  the  shell  is  plain,  with  the  exception 
of  very  fine  concentric  striae  which  appear  to  conform  to 
the  shape  of  the  shell  at  its  different  stages  of  growth. 

I know  of  no  other  species  in  the  rocks  of  this  age,  with  which  this  can  easily  be 
confounded.  It  has  much  the  general  form  of  the  Genus  Eatonia  as  given  by  Hall, 
but  is  very  clearly  a true  lihynchonella.  This  species  bears  considerable  resemblance 
to  R.  missouriensis  (Shumard,  Geological  Report  of  Missouri,  PI.  fig.  5),  but  is 
less  angular  than  that  species,  not  so  broad  on  the  top  of  the  elevation,  and  the 
plications  are  not  so  large.  Perfect  specimens  of  R.  missouriensis  show  very  fine 
longitudinal  strite,  which  are  not  mentioned  in  Shumard’s  descriptions;  which  fea- 
ture this  species  never  possesses.  There  are  also  other  difierences. 

Geological  position  and  localities.  In  Coal  measure  shales  at  Graysville,  Illinois; 
and  in  the  Big  Creek  limestone,  Indiana. 


7 


50 


BllACIIIOPODA. 


Uliynelioiiella  c.\])laiiata  ( n.  s.)- 

Shell  small,  sub-triangular,  very  gibbous ; beak  small 
and  pointed,  straight.  Ventral  valve  nearly  or  slightly  con- 
vex to  the  middle,  from  which  point  it  is  abruptly  curved 
upwards,  forming  a broad  and  well  defined  sinus,  having 
one  large,  low  plication  in  its  bottom  occupying  one-half 
the  entire  breadth  of  the  sinus ; sides  of  the  extension 
nearly  parallel.  Dorsal  valve  extremely  ventricose,  greatest 
elevation  in  front,  gradually  curving  back  to  the  beak, 
which  is  small  and  closely  incurved  beneath  that  of  the 
opposite  valve  ; the  sides  of  the  front  slope  rapidly  from 
the  edges  of  the  elevated  plications  to  about  two-thirds  the 
depth  of  the  valve,  where  they  come  in  contact  with  the 
next  plication,  which  stands  out  abruptly  in  a stair-like 
projection,  from  which  the  sides  are  perpendicular  to  the 
lower  edges  of  the  valve. 

Surface  marked  by  eight  simple  angular  plications,  which 
do  not  extend  quite  to  the  beak;  two  of  which  are  very 
strong,  and  elevated  on  the  dorsal  valve  into  a mesial 
prominence,  with  two  corresponding  depressions  in  the 
sinus  of  the  other  valve  ; the  plications  on  each  side  of  the 
prominence,  except  the  first,  are  indistinct,  particularly 
the  outer  ones,  which  are  scarcely  perceptible.  There  are 
also  traces  of  very  fine  concentric  striae  crossing  the  plica- 
tions, and  having  a zigzag  direction,  which  are  visible  only 
on  the  front  of  the  shell. 

This  species  bears  some  resemblance  to  JR.  woriheni  of  Hall,  described  in  a pam- 
phlet entitled  “Descriptions  of  New  Species  of  Fossils  from  the  Carboniferous 
limestone  of  Indiana  and  Illinois;”  but  is  considerably  more  elevated  in  front,  not 
so  angular  in  outline,  and  H.  wortheni  does  not  possess  any  plications  except  the 
two  which  are  elevated  into  the  mesial  prominence. 

Geological  position  and  locality.  In  the  Kaskaskia  division  of  the  Carboniferous 
limestone.  I have  also  a specimen,  doubtfully  labeled,  from  the  Coal  measures  near 
New-IIarmony,  Indiana. 


BRACIIIOPODA. 


51 


Kliyiiciioiiclla  carboiiaria  ( n.  s.). 

Shell  transversely  subelliptical  in  outline,  when  viewed 
from  above,  with  a small  sharp  beak  projecting  beyond  the 
general  outline ; and  when  seen  in  front,  of  a somewhat 
quadrangular  form,  having  the  gides  rounded.  Ventral  valve 
very  shallow,  slightly  convex  near  the  beak  and  on  the 
sides,  with  the  center  depressed  and  prolonged  into  a quad- 
rate extension,  which  fits  into  the  sinus  in  the  border  of 
the  opposite  valve.  Dorsal  valve  very  much  elevated,  espe- 
cially in  front,  from  which  point  it  gradually  slopes  with 
but  little  curve  to  the  beak;  the  lateral  slopes  rounded 
down  to  the  sides  of  the  front. 

Surface  marked  by  about  thirty  simple  plications,  which 
are  rounded  or  subangular  in  the  sinus  and  on  the  mesial 
elevation,  and  flattened  on  the  sides  of  the  shell  : ten  of 
these  plications  are  elevated  on  the  dorsal  valve  and  a cor- 
responding number  depressed  on  the  ventral,  which  depres- 
sion and  elevation  do  not  extend  past  the  middle  of  the 
shell  ; the  cardinal  areas  of  the  dorsal  valve  are  somewhat 
depressed. 

This  species  may  be  compared  with  /?.  cooperensis  of  Shumard  (Geologica^ 
Eept.  Missouri),  which  it  somewhat  resembles  in  general  outline,  but  is  more  trans- 
versely elongate,  and  has  a greater  number  and  smaller  plications.  The  geological 
position  is  also  very  different,  his  being  found  in  rocks  of  the  age  of  the  Chemung 
of  New-York,  this  being  from  the  Upper  Coal  measure  rocks. 

Geological  position  and  locality.  In  the  Upper  Coal  measure  limestone,  near 
Farmington,  Illinois. 

Itliyiiclioiiella  algeri  ( n.  s.). 

Shell  small,  varying  from  suborbicular  to  transversely 
subelliptical,  and  sometimes  subovate,  usually  gibbous,  some- 
times in  young  specimens  depressed  convex ; beak  straight 
and  pointed.  Ventral  valve  shallow,  depressed  convex  near 
the  beak,  and  becoming  broadly  sinuate  and  prolonged  into 
a broad  subquadrangular  extension  in  front.  Dorsal  valve 
ventricose,  somewhat  regularly  convex,  elevated  in  front ; 
beak  incurved  beneath  that  of  the  opposite  valve. 


52 


BRACHIOPODA. 


Surface  marked  by  from  nine  to  fourteen  simple  sub- 
angular  plications,  which  are  distinct  in  front,  but  become 
obsolete  near  the  middle  of  the  shell,  from  three  to  four  of 
which  are  elevated  on  the  front  of  the  dorsal  valve,  and  a 
corresponding  number  depressed  in  the  opposite  valve  ; and 
also  by  very  fine  undulating  concentric  striae,  and  a few 
zigzag  lines  of  growth  on  the  front  of  the  shell,  most  dis- 
tinct on  the  elevation  and  in  the  sinus. 

The  only  species  with  which  this  can  possibly  be  confounded  is  R.  nucleata  of 
Hall  (Geological  Report  of  Iowa,  PI.  23,  fig.  2);  but  it  is  not  triangular,  and  the 
plications  are  larger,  fewer  in  number,  and  do  not  extend  to  the  beak  as  in  that 
species.  The  geological  position  is  also  different,  the  above  cited  occurring  in  the 
middle  of  the  Carboniferous  limestone  series. 

Geological  position  and  locality.  In  coal  measures  at  Big  creek,  near  New  Har- 
mony, Indiana. 


LAMELLIBRANCHI ATA . 


Leda  oweiii  ( n.  s. ). 

Shell  somewhat  above  the  medium  size,  rather  more 
than  twice  as  long  as  wide,  very  gibbous  and  inflated  ante- 
riorly, rapidly  tapering  and  attenuate  posteriorly  ; beaks 
somewhat  prominent,  incurved  and  closely  approximate, 
situated  near  the  anterior  extremity  of  the  shell  and  point- 
ing anteriorly ; anterior  extremity  rapidly  sloping  from 
the  beak  downward,  and  rounded  below.  Ventral  margin 
broadly  curved,  and,  a little  anterior  to  the  middle,  some- 
what projecting ; posterior  extremity  narrowly  rounded  ; 
hinge  line  posterior  of  the  beaks  straight,  or  very  slightly 
arched  ; hinge  with  ten  teeth  on  the  anterior  side  of  the 
beak,  some  of  which  are  comparatively  large,  and  about 
forty-one  or  two  on  the  posterior  side ; those  beneath  the 


LAMELLIBRANCHIATA. 


53 


beak  extremely  small,  but  gradually  increasing  in  size  as 
they  approach  the  posterior  extremity,  except  two  or  three 
of  the  terminal  ones,  which  are  smaller.  Exterior  of  the 
shell  marked  by  a slight  depression,  which  extends  from 
the  beak  to  the  lower  side  of  the  posterior  extremity,  and 
by  strong  irregular  concentric  bands  or  folds  which  become 
finer  and  less  distinct  as  they  approach  the  cardinal  line. 

Geological  position  and  locality.  In  the  Coal  measures  : mouth  of  Rush  creek, 
Indiana,  five  miles  below  New-Harmony. 


Leda  gibbosa  (n.  s. ). 

Shell  of  medium  size,  once  and  a half  as  long  as  wide, 
ovoid  anteriorly,  elongate  and  moderately  attenuate  poste- 
riorly ; beaks  elevated  and  slightly  anterior  of  the  middle 
of  the  shell,  incurved  and  pointing  posteriorly ; cardinal 
line  curved,  and  on  the  posterior  side  sharply  elevated,  with 
a distinct  depression  between  it  and  the  umbonal  slope. 
Ventral  margin  regularly  curved;  escutcheon,  broad  and 
faintly  depressed. 

Surface  marked  by  fine  but  distinctly  elevated  concen- 
tric striae. 

This  species  differs  from  Leda  bellastriata  of  Stevens  (Am.  Journal  of  Science, 
Vol.  XXV.,  P.  261),  in  being  much  shorter  in  proportion  to  its  width,  much  less 
contracted  and  attenuate  posterioily,  and  more  ventricose. 

Geological  position  and  locality.  In  Coal  measures  on  the  Wabash  river,  five  miles 
below  New-Harmony,  Indiana. 


Leda  polita  (n.  s.). 

Shell  small,  somewhat  elongated  posteriorly,  about 
twice  as  long  as  wide,  broadly  subovate,  widest  anterior 
of  the  middle  : beaks  very  small,  pointed  towards  the 
shortest  end,  incurved  and  closely  approximate,  situated 
about  one  third  the  entire  length  of  the  shell  from  the  an- 
terior extremity,  which  is  sharply  rounded  ; the  curve  of 
the  ventral  margin  is  a very  perfect  semi-oval,  rounded 


54 


LAMELLIBRANCHIATA. 


abruptly  at  the  posterior  end  ; hinge  line  on  the  posterior 
side  of  the  beak  straight,  or  slightly  depressed.  Surface  of 
the  shell  appearing  smooth  to  the  unassisted  eye,  but 
under  a magnifier,  of  ordinary  power,  it  is  covered  with 
very  fine  concentric  strim  which  are  recurved  as  they  ap- 
proach the  cardinal  line  of  the  posterior ; and  also  by  one 
or  more  faintly  depressed  lines  along  the  posterior  umbo- 
nal  slope  ; teeth  unknown. 

This  species  is  allied  to  L.  bellastriata  (Stephens,  Am.  Jour,  of  Science,  Vol. 
xxv),  but  is  not  so  much  prolonged  at  the  posterior  end,  the  cardinal  line  is  not 
so  much  depres.sed,  and  it  does  not  possess  the  beautiful  distinct  concentric  striae 
which  is  so  marked  a character  of  that  species. 

Geological  position  and  locality  In  the  Coal  measures  at  Dr.  E.  Hall’s  mill.  Pope 
creek,  Knox  county,  Illinois. 

^iiciila  parva  (n.  s.). 

Shell  minute,  subtriangular,  somewhat  gibbous  at  the 
beaks,  which  are  small,  incurved,  approximate,  pointing 
toward  and  terminating  the  anterior  extremity  ; cardinal 
line  straight  to  near  the  beaks,  where  it  is  slightly  curved 
downward  ; cardinal  line  and  anterior  slope  are  at  right 
angles  to  each  other.  Ventral  margin  beautifully  and 
gradually  curving  upward  to  the  posterior,  which  is  sharply 
rounded.  Interior  of  the  hinge  unknown. 

Surface  marked  by  comparatively  coarse,  regular,  sharp, 
concentric  strim. 

This  shell  has  the  general  appearance  of  N.  shumardana  of  Hall.  (Trans.  Albany 
Inst.,  Vol.  iv,  Nov.  185G),  but  differs  from  it  entirely  in  the  surface  structure;  that 
species  being  only  finely  striated,  as  are  alt  shells  of  this  class,  when  destitute  of 
ornamental  surface  structure  ; while  the  makings  of  this  species  are  of  an  orna- 
mental nature,  sufficiently  strong  to  be  considered  of  specific  importance. 

Geological  position  and  locality.  In  the  Coal  measures  at  Danville,  Illinois. 

^'ucula  cylmdriciis  (n.  s. ). 

Shell  small,  about  twice  as  long  as  wide,  subcylindrical 
in  form ; valves  most  ventricose  a little  anterior  to  the  mid- 


LAMELLIBRANCHIATA. 


die,  from  which  point  they  slope  abruptly  to  the  posterior 
extremity,  and  but  slightly  to  the  anterior  : beaks  short, 
obtuse,  almost  anterior,  and  pointing  forward ; depression 
beneath  them  extremely  small  : hinge  lines,  posterior  to  the 
beaks,  straight  or  slightly  arching,  and  nearly  at  right 
angles  to  the  anterior  slope.  Teeth  unknown. 

Surface  smooth  and  polished,  except  fine  concentric 
lines  of  growth,  which  are  verj^  indistinct. 

Geological  position  and  locality.  In  Coal  measures,  Carnahan’s  Coal  mine, 
Mercer  county,  Illinois. 


Astaitella  varica  (n.  s.). 

Shell  subcircular,  only  moderately  gibbous  but  most  so 
on  the  umbones,  beaks  anterior  to  the  centre  of  the  shell, 
approximate,  sharp  and  pointing  forward ; anterior  end 
deeply  concave  under  the  beak  and  rounded  below.  An 
oblique  ridge  extends  from  the  beak  in  the  direction  of  the 
posterior  basal  margin,  becoming  faint  or  imperceptible 
before  reaching  the  front;  ligamental  area  deeply  marked. 

Surface  marked  by  very  strong,  somewhat  distant  con- 
centric ridges,  which,  when  perfect,  are  raised  into  thin, 
sharp  expansions,  their  number  on  the  specimen  under 
description,  which  is  about  half  an  inch  wide,  is  ten.  The 
spaces  between  them  are  regularly  rounded. 

Geological  position  and  locality.  In  Coal  measures,  Springfield,  Illinois. 

Ediiioiidia  conceiitrica  ( n.  s.). 

Shell  longeT  than  high,  subelliptical,  ventricose  on  the 
umbones ; beaks  about  one  fourth  distant  from  the  anterior 
to  the  posterior  of  the  shell,  prominent,  slightly  incurved 
and  pointing  to  the  anterior ; margins  quite  regularly 
curved,  except  the  dorsal,  which  is  nearly  straight. 

Surface  marked  by  concentric  wrinkles  or  folds,  irregu- 


56 


LAMELLIBRANCHIATA. 


lar  in  their  distance  from  each  other,  sometimes  two  or 
three  appear  to  be  crowded  upon  each  other.  Minute  sur- 
face markings  unknown. 

Geological  position  and  localities.  In  the  Coal  measures,  Carnahan’s  Coalmine, 
Mercer  county  (Illinois),  Big  Creek  (Indiana),  Charbonier  (Missouri). 


All<»risiiia  clavata  ( n.  s.). 

Shell  of  medium  size,  elongated  posteriorly,  broad  and 
gibbous  at  the  beaks,  rapidly  sloping  from  the  umbones  to 
the  anterior  extremity,  and  gradually  decreasing  in  width 
and  thickness,  as  it  approaches  the  posterior  ; beaks  approx- 
imate and  incurved,  situated  one-fifth  of  the  entire  length 
of  the  shell  from  the  anterior  extremity ; anterior  margin 
rapidly  sloping  from  the  beaks  to  the  point  of  greatest 
length,  which  is  situated  below  the  middle  of  the  shell  and 
regularly  rounded  below  to  the  ventral  margin,  which  is 
straight  or  slightly  sinuate  a little  anterior  of  the  center  of 
the  shell,  and  regularly  curving  upward  as  it  approaches 
the  posterior  extremity ; posterior  extremity  sharply 
rounded  ; cardinal  margin  concave  or  slightly  depressed  in 
the  middle.  On  the  surface  of  the  shell,  between  the  ante- 
rior and  posterior  umbonal  ridges,  there  is  a flattened  or 
slightly  concave  space  extending  like  a sinus  from  the  beak 
to  the  base  or  ventral  margin  of  the  shell. 

The  surface  of  the  shell  is  marked  by  strong  concentric 
ridges  which  mark  the  different  stages  of  growth,  most  dis- 
tinct on  the  middle  of  the  shell. 

Geological  position  and  locality.  In  the  Kaskaskia  division  of  the  Carboniferous 
limestone  series,  Chester,  Illinois. 


Allorisma  simiata  (n.  s.). 

Shell  below  medium  size,  prolonged  posteriorly,  thick, 
and  extremely  gibbous  along  the  posterior  umbonal  slope ; 
beaks  prominent,  projecting  considerably  above  the  cardi- 


LAMELLIBRANCHIATA. 


67 


nal  line,  closely  approximate  and  incurved,  situated  a little 
more  than  one-third  the  entire  length  of  the  shell  from  the 
anterior  extremity.  Anterior  margin  rapidly  sloping  from 
the  beaks  to  the  extremity,  and  sharply  rounded  below. 
Ventral  margin  strongly  sinuate,  the  sinus  being  situated 
anterior  to  the  middle,  and  gradually  rounded  to  the  pos- 
terior extremity,  which  is  narrow ; cardinal  line  straight 
from  the  beaks  to  the  posterior  extremity. 

The  surface  of  each  valve  is  marked  by  a broad  shallow, 
but  distinctly  defined  depression  extending  from  the  beak 
to  the  base  or  ventral  margin  of  the  shell  between  the  an- 
terior and  posterior  umbonal  slopes. 

Surface  marked  by  strong  concentric  ridges  parallel 
with  the  borders  of  the  shell. 

This  species  differs  from  the  last  one  described,  in  being 
a shorter  shell  in  proportion  to  its  depth,  in  its  more  pro- 
minent beaks  and  in  the  strong  sinus  marking  the  centre 
of  the  valves,  and  in  being  much  more  gibbous,  especially 
along  the  umbonal  slope. 

Geological  position  and  localities.  In  the  Kaskaskia  division  of  the  Carboniferous 
limestone,  Kaskaskia  and  Chester,  Illinois. 


Myaliiia  swallovi  (n.  s.). 

Shell  small  subtriangular,  height  once  and  a half  the 
length,  somewhat  gibbous  on  the  umbones  ; cardinal  border 
oblique  and  slightly  arched ; posterior  margin  subparallel 
with  the  umbonal  ridge,  and  forming  with  the  cardinal 
line  an  angle  of  130®  ; ventral  margin  strongly  rounded ; 
distance  across  the  ventral  extremity  of  the  shell  some- 
what less  than  the  width  above  ; anterior  extremity  pro- 
jecting a little  beyond  the  point  of  the  beak,  and  somewhat 
swollen  or  inflated  between  the  beak  and  the  margin  of  the 
valve,  with  a shallow  sinus  or  depression  between  it  and 
the  umbonal  ridge,  running  from  the  beak  to  the  centre  or 
8 


58 


LAMELLIBRANCHIATA. 


middle  of  the  buccal  border:  buccal  border  straight  or 
very  slightly  concave ; umbonal  ridge  prominent,  slightly 
angular,  and  declining  with  a gradual  slope  to  the  posterior 
margin  ; anterior  slope  very  abrupt,  nearly  at  right  angles 
with  the  plane  of  the  shell.  The  umbonal  ridge  is  curved 
in  the  upper  part  of  the  shell  toward  the  posterior  extre- 
mity, but  afterward  reflected,  and  terminating  on  the 
anterior  side  of  the  ventral  portion  of  the  shell.  The 
surface  of  the  shell  is  marked  with  extremely  fine  concen- 
tric striae,  which  are  bent  abruptly  as  they  cross  the 
umbonal  ridge  ; also  with  a few  concentric  lines  of  growth. 

This  is  a very  pretty  species,  and  is  somewhat  closely  related  to  M.  recta  of 
Shumard  (Ext.  from  Trans.  Acad.  Science,  St.  Louis,  Vol.  I,  No.  2,  if  we  have 
succeeded  in  rightl_)  referring  that  species);  but  it  differs  in  having  the  beaks  not 
quite  terminal  and  less  acute,  the  cardinal  margin  more  arched,  and  the  umbonal 
ridge  not  so  angular;  the  ventral  portion  or  base  of  the  shell  is  not  so  wide  as  in 
his  species,  in  comparison  with  the  width  from  the  posterior  end  of  the  cardinal 
line  to  the  middle  of  the  buccal  border. 

Geological  position  and  locality.  In  the  Coal  measures  at  Charbonier,  and  12 
miles  northwest  of  Richmond,  Missouri. 


GASTEROPODA.' 


Bellerophoii  ellipticus  ( n.  s.). 

Shell  large,  very  thin  and  fragile  ; inner  volutions 
small,  and  but  little  expanding ; outer  volution  large, 
broadly  expanded,  almost  flattened ; aperture  very  trans- 
verse elliptical,  as  wide  again  as  long ; lip  sharp,  outer 
portion  notched  ; posterior  portion  deeply  sinuate,  where 
it  passes  over  the  preceding  volution,  and  forms  a callus 
of  equal  thickness  with  the  other  portion  of  the  lip.  Dor- 
sum marked  in  the  earlier  stages  by  a very  shallow, 
narrow  groove,  which  becomes  broader,  and  has  the  centre 


GASTEROPODA. 


59 


elevated  as  it  approaches  the  front  of  the  last  volution, 
into  a somewhat  sharper  and  prominent  carina,  which 
terminates  in  the  notch  in  front.  Umbilicus  open,  and  of 
moderate  size. 

Surface  of  the  shell  covered  with  very  fine  longitudinal 
strim,  which  terminate  abruptly  at  about  the  middle  of  the 
expanded  portion  of  the  last  volution,  the  remainder  of 
which  is  marked  by  broad  transverse  undulations,  or 
wrinkles,  and  also  by  concentric  or  transverse  striae,  much 
finer  than  the  longitudinal  striae,  giving  a finely  cancellated 
structure  to  the  shell  where  the  two  sets  cross  each  other. 
The  concentric  striae  and  the  wrinkles  are  bent  abruptly 
backward,  as  they  cross  the  carina  in  front,  and  but 
slightly  over  the  groove  in  the  earlier  stages  of  growth. 

Specimens  of  this  species,  when  found  in  limestones  or 
very  compact  shales,  are  usually  in  the  state  of  casts, 
owing  to  the  thinness  of  the  shell  and  the  ornamented 
structure  of  the  exterior,  which  adheres  more  firmly  to 
the  matrix  than  to  the  smooth  interior ; and  in  this  state 
the  impression  of  the  striae  appear  like  low  distant  plica- 
tions, which  is  owing  to  some  of  the  striae  being  stronger 
than  others,  and  making  a deeper  impression. 

Geological  position  and  localities.  In  the  Coal  measures,  at  Dr.  E.  Hall’s  Mill, 
Pope  Creek,  Knox  Co.;  Carnahan’s  Mine,  Mercer  Co.;  and  Mr.  Fisher’s  Mine, 
near  Lacon,  Illinois. 


Belleroplion  vittatns  ( n.  s.). 

Shell  of  medium  size,  subglobose,  somewhat  rapidly 
expanding  at  the  sides.  Aperture  semilunate,  broadly 
transverse,  but  rather  shallow  : outer  lip  very  thin,  and 
expanding  at  the  sides  into  sharply  rounded,  ear-like  exten- 
sions, very  broadly  and  deeply  sinuate ; and  when  the 
specimen  is  held  with  the  plane  of  the  mouth  horizontal 
with  the  axis  of  the  shell,  the  sinus  extends  nearly  its 
entire  width  : notch  shallow,  rounded  at  the  bottom,  and 


60 


GASTEKOPODA. 


about  an  eighth  of  an  inch  wide  in  adult  specimens.  The 
inner  side  of  the  mouth  is  formed  entirely  by  the  preced- 
ing volution,  without  thickening  or  callosity.  Axis  of  the 
shell  imperforate. 

Surface,  except  the  outer  half  of  the  last  volution, 
marked  by  about  twenty-four  sharp,  revolving,  nearly 
parallel  bands,  some  of  which,  on  the  sides  of  the  shell,  are 
interrupted,  forming  broken  striae  or  elongated  nodes. 

This  species  has  usually  been  referred  to  B.  urii,  of  Fleming,  and  has  been 
figured  as  such  by  Messrs.  Norwood  and  Pratten  in  the  Transactions  of  the 
Academy  of  Sciences  of  Philadelphia,  June  1855;  but  on  careful  comparison  with 
figures  and  descriptions  by  De  Koninck,  Phillips  and  others,  it  proves  to  be  a 
very  distinct  and  well  marked  species.  B.  urii  is  characterized  by  from  36  to  38 
keels,  or  revolving  bands;  while  this  species,  by  an  examination  of  a large  number 
of  specimens  before  us,  presents  no  more  than  26,  and  rarely  more  than  22.  The 
principal  points  of  separation,  however,  consist  in  the  nature  of  the  axis,  and  in 
the  form  of  the  sides  of  the  mouth.  In  B.  urii  the  sides  of  the  mouth  are  connected 
by  a callosity  to  the  preceding  volution  in  front  of  the  axis  of  the  shell,  while  in 
this  species  they  are  free,  and  stand  out  somewhat  distant  from  the  volution. 

B.  urii  has  the  structure  of  an  umbilicate  shell,  except  the  perforation  being 
filled  by  callosity,  leaving  only  a slight  depression  on  the  sides  of  the  shell,  expressed 
as  follows  by  De  Koninck;  “ Z^s  ombilices  sont  remplacSs  par  des  petites  fassettes 
arrondies  et  peu  profondes.”  In  our  shell  the  volutions  do  not  pass  around  the  cen- 
tre, but  their  inner  edges  form  the  axis.  This  peculiarity  is  not  only  of  specific 
importance,  but  actually  places  the  shell  in  a different  subdivision  of  the  genus. 

Geological  position  and  localities.  In  Coal  measures  at  the  mouth  of  Rush  Creek 
(Indiana),  Graysville  (Illinois). 


Belleroplioii  blaiiyanus  ( n.  s.). 

Shell  small,  subglobose,  rapidly  expanding  on  the  sides 
in  front.  Aperture  broadly  transverse,  semilunate,  deeply 
impressed  by  the  preceding  volution ; outer  lip  thin;  sides 
attached  by  a slight  callosity  to  the  preceding  volution  in 
front  of  the  axis  of  the  shell. 

This  shell  is  umbilicate  in  form,  though  imperforate, 
the  cavity  being  filled  by  callosity,  except  a small  circular 
indentation. 

Surface  marked,  except  the  front  or  last  half  of  the  outer 
volution,  by  about  sixteen  sharp,  nearly  parallel,  longitu- 


GASTEROPODA. 


61 


dilial  or  revolving  bands,  which  are  not  always  continuous  ; 
and  on  the  sides,  around  the  axis,  by  a few  rows  of  elon- 
gated nodes,  which  appear  to  be  broken  or  undeveloped 
revolving  bands,  which  extend  much  farther  upon  the  front 
of  the  shell  than  the  other  bands ; the  portion  of  the  front 
not  thus  covered  is  smooth,  except  some  very  fine  con- 
centric striae,  and  a double  carina  along  the  dorsum,  which 
is  sometimes  very  faintly  visible. 

This  shell  is  most  nearly  related  to  B.  urii  of  Europe,  but  differs  from  it  in  hav- 
ing not  more  than  half  the  number  of  revolving  bands,  and  in  the  sides  of  the  front 
half  of  the  outer  volution  being  covered  by  broken  ribs  or  nodules. 

Geological  position  and  localities.  In  Coal  measures  in  Saline  and  Peoria  coun- 
ties, and  at  Danville  and  Graysville,  Illinois. 


Belleroplioii  steveiisianiis  ( n.  s.). 

Shell  small,  slightly  elongate,  gradually  expanding 
toward  the  front.  Aperture  transverse,  sub-semilunate, 
sometimes  triangular,  modified  by  the  preceding  volution : 
outer  lip  thin,  sides  very  much  thickened  by  an  overlap- 
ping callosity ; dorsum  furnished  with  a rib-like  band, 
bounded  on  each  side  by  a sharp  narrow  depression. 

Surface  beautifully  ornamented  by  concentric  strim  or 
lines  of  growth,  which  curve  forward  on  the  sides  of  the 
volution  and  slightly  back  on  the  central  band. 

Geological  position  and  locality.  In  Coal  measure  shales  in  the  vicinity  of  Spring- 
field,  Illinois. 


Pleurotomaiiii  beckwUliaiia  (n.  s.). 

Shell  small ; whorls  four  to  five,  rounded  both  above 
and  below,  rapidly  and  regularly  expanding  except  at  the 
aperture  below  where  the  shell  is  deflected  or  more  abruptly 
widened ; mouth  subcircular ; outer  lip  thin,  and  broken 
away  in  the  specimen  under  description ; columella  lip  but 
slightly  thickened. 

Surface  beautifully  ornamented  by  fine  but  very  dis- 


62 


GASTEROPODA. 


tinct  longitudinal  or  revolving  striae,  and  by  folds  or 
wrinkles  extending  back  obliquely  from  the  suture  line 
over  the  upper  part  of  the  whorls. 

From  the  centre  of  the  outer  lip  there  is  a narrow  flat- 
tened, scarcely  elevated  band,  extending  longitudinally 
over  the  whorl,  the  lower  edge  of  which  is  most  prominent. 

This  species  has  the  general  form  of  P.  carbonaria  (N.  and  P.),  but  is  a much 
less  shell,  and  is  finely  striated,  while  that  is  marked  by  strong  bands  or  revolving 
ribs. 

Geological  position  and  locality.  So  far  as  I am  aware,  this  beautiful  shell  has 
only  been  found  in  the  Coal  measure  shales  over  the  upper  coal  seam  at  Danville, 
Illinois. 


^atica  slmmardi  (n.  s.). 

Shell  much  elongated  or  subfusiform,  smooth  except 
several  strong  irregular  lines  of  growth ; substance  of  the 
shell  rather  thick.  Spire  produced ; number  of  whorls 
unknown ; suture  impressed ; whorls  flattened  above,  and 
sharply  rounded  below.  Columella  thickened  above,  and 
covered  on  the  upper  side  of  the  aperture  by  a heavy  cal- 
lus, which  entirely  conceals  the  umbilicus.  Aperture 
subova te,  nearly  two-thirds  the  length  of  the  last  volution  ; 
greatest  diameter  in  the  direction  of  the  axis  of  the  shell : 
outer  lip  sharp. 

This  shell  differs  from  N.  ventrica  (N.  and  P.,  Journal  Acad.  Nat.  Sci.,  Jan. 
1855)  = N.  magister  (Stevens,  Amer.  Journal  of  Science,  Vol.  xxv),  in  being  a 
much  more  elongate  shell ; the  comparative  length  being,  in  a specimen  of  the  same 
diameter,  as  two  to  one;  in  not  possessing  the  radiating  lines  running  from  the 
suture  into  the  body  of  the  whorl,  and  in  the  possession  of  the  very  massive 
callosity. 

Geological  position  and  locality.  In  Coal  measures,  Lasalle,  Illinois. 

Platyostoiiia  peorieiisis  ( n.  s.) 

Shell  of  iHedium  size,  somewhat  elongated  subglobose, 
composed  of  about  two  volutions,  which  are  contiguous, 
expanding  quite  rapidly,  the  outer  one  much  inflated  near 
the  aperture,  which  is  longitudinally  ovate,  widest  below ; 


GASTEROPODA. 


63 


spire  usually  depressed  (sometimes  a little  elevated) ; 
sutures  deep  and  distinct  : substance  of  the  shell  very  thin. 

Surface  entirely  destitute  of  plications  or  folds,  and 
marked  only  by  very  fine  concentric  lines,  apparently  of 
growth. 

This  species  possesses  the  characters  common  to  all  the 
species  of  this  genus ; but  we  know  of  no  shell  from  rocks 
of  this  age,  hitherto  described,  with  which  it  can  be  con- 
founded, or  with  which  it  is  necessary  to  draw  comparisons. 

Geological  position  and  localities.  In  the  Upper  Coal  measure  limestone,  Peoria, 
Fulton,  and  many  other  counties  in  Illinois. 

]\autilus  forbesiaiius^  ( n.  s.). 

Shell  subglobose,  convolute,  not  embracing,  moderately 
increasing  in  width  and  regularly  convex  on  the  back, 
sharply  rounded  on  the  sides  and  sloping  rapidly  into  the 
umbilicus,  which  is  large  and  deep,  disclosing  all  of  the 
preceding  volutions.  Aperture  transversely  subelliptical, 
twice  as  wide  as  high,  but  slightly  modified  by  the  dorsal 
convexity  of  the  preceding  volution.  Septa  moderately 
distant ; relative  distance  somewhat  less  than  one  fourth 
the  breadth  of  the  shell  at  the  same  place,  somewhat 
deeply  concave,  and  presenting  a moderately  shallow 
receding  curve  on  the  back  of  adult  specimens,  but  much 
deeper  in  young  individuals.  Siphuncle  rather  large,  ven- 
trally  situated,  causing  in  the  septa  a funnel-shaped 
depression. 

Surface  ornamented  on  each  side  by  a line  of  large, 
rounded,  somewhat  distant  nodes,  which  form  a very  con- 
spicuous feature  of  the  fossil.  Surface  of  the  shell  unknown. 

This  species  has  a slight  resemblance  to  iV.  ferratus  of  Cox  (Geo.  Report  Ken- 
tucky, Vol.  iii),  but  differs  in  being  less  globose,  increasing  less  rapidly  in  the 
diameter  of  the  voUtions,  and  more  particularly  in  possessing  the  large  nodes  on 
each  side  of  the  shell. 

Geological  position  and  locality.  In  Coal  measures,  Carnahan’s  mine,  Mercer 
county,  Illinois. 

• Named  in  honor  of  P.  S.  Forbes,  Esq.,  of  New-York  City,  late  Consul  to  Pekin, 


G4 


GASTEROPODA. 


\iuitiliis  illhioieii$LS  ( n.  s.). 

Shell  very  large  ; the  greater  diameter,  of  a specimen 
possessing  a little  less  than  three  volutions,  measuring  full 
nine  inches,  and  nearly  four  in  the  greatest  breadth  of  the 
volution,  which  is  still  septate,  the  outer  chamber  having 
been  broken  away  ; convolute  whorls  joining,  but  not  em- 
bracing. Form  of  the  volutions  subquadrate,  transverse  ; 
dorsum  flat  (in  the  younger  stages  of  growth  appears  to 
be  slightly  convex,  becoming  slightly  concave  in  large  indi- 
viduals), sides  inflated,  greatest  Avidth  a little  to  the  ven- 
tral side  of  the  centre  ; edges  of  the  periphery  ornamented 
by  a row  of  very  broad  nodes,  Avhich  present  a series  of 
regular  undulations  when  viewed  across  the  angle  of  the 
shell ; umbilicus  very  broad,  of  moderate  depth,  the  sides 
regularly  rounded  on  to  the  successive  volutions.  Septa 
rather  distant ; at  a point  Avhere  the  volution  measures  two 
inches  from  the  ventral  to  the  dorsal  side,  their  dorsal 
edges  are  distant  five  eighths  of  an  inch,  and  increase  in 
distance  with  the  groAvth  of  the  shell,  somcAvliat  deeply 
concave,  recurving  rather  strongly  on  the  dorsum  and  but 
moderately  on  the  sides.  Position  of  the  siphuncle  un- 
known. 

Surface  of  the  shell  marked  by  strong  transverse  lines 
of  growth. 

This  species  is  somewhat  closely  allied  to  iV.  planovolvus  of  Siiumard  (Trans. 
Acad,  of  Sci.  St.  Lous,  Vol.  i,  No.  2),  but  differs  in  being  a much  larger  shell,  in 
having  more  distant  septa,  and  in  the  large  strong  nodes  on  the  edges  of  the  dor 
sum  ; his  species  not  being  described  as  a nodose  shell. 

Geological  position  and  locality.  Upper  Coal  measure  limestone,  Lasalle,  Illinois. 


Note. — For  a description  of  the  Genus  Ambocelia,  recently  established  by  Prof.  James 
HalLj  see  Regents'  Report  of  the  State  of  New-York  for  the  present  year. 


CEPHALOPODA. 


65 


IVautiliis  qiiadiaiigiilus  ( n.  s.). 

Shell  of  medium  size,  somewhat  discoid,  convolute, 
slightly  embracing.  Volutions  increasing  in  size  but  mode- 
rately, the  increase  being  more  in  the  dorso-ventral  than 
in  the  lateral  diameter  ; volutions  quadrate  in  form  ; in 
young  specimens  the  transverse  diameter  is  proportionately 
greater,  becoming  more  equal  in  older  specimens,  and  in 
some  instances  the  dorso-ventral  diameter  becomes  con- 
siderably greater  than  the  lateral  ; sides  of  the  volutions 
flat,  slightly  rounded  in  front.  Volutions,  in  a specimen 
of  two  and  a half  inches  in  greatest  diameter,  little 
more  than  two  in  number,  and  ornamented  by  a line  of 
prominent  lanceolate  nodes  on  each  of  the  outer  angles  ; 
and  another  line  on  each  side  of  the  centre  of  the  dorsum 
in  old  and  medium-sized  specimens,  which  are  not  deve- 
loped in  young  individuals,  though  in  adults  they  become 
more  prominent  than  the  marginal  lines,  and  leave  a deep 
rounded  channel  between  them  : they  are  also  arranged  in 
transverse  lines  across  the  back  of  the  shell  ; and  still 
another  indistinctly  developed  line  of  nodes  along  the 
outer  edge  of  the  umbilicus,  most  prominent  in  young- 
individuals.  Umbilicus  broad,  exposing  almost  the  entire 
breadth  of  the  different  volutions;  the  slope  from  the 
inner  line  of  nodes  to  the  j>receding  volution  precipitous. 
Septa  moderately  distant  ; the  distance  in  a well  pre- 
served specimen  being  about  one  third  the  transverse 
diameter  of  the  shell,  forming  on  the  back  of  the  shell, 
when  exposed,  a rather  deep,  and  on  the  sides  a moderately 
recurved  sinus,  which  is  owing  to  the  quadrangular  form 
of  the  volutions.  The  exact  position  of  the  siphon  is  not 
determined,  but  it  is  apparently  situated  on  the  ventral 
margin. 

Surface  of  the  shell,  in  well  preserved  specimens,  is 
marked  by  very  fine  transverse  striae,  which  form  on  the 
back  of  the  shell  a deep  receding  curve. 

9 


66 


CEPHALOPODA. 


This  is  quite  an  abundant  species  in  the  rocks  of  the  Coal  measures,  and  espe- 
cially so  at  Graysville,  Illinois,  though  usually  in  fragments  : the  specifie  characters 
are,  however,  so  marked  as  to  render  them  easily  recognized. 

^luUihts  iimloc’iiiiiiatus  (n.  s.). 

Associated  with  the  above  species  there  is  another  quite 
distinct,  though  allied  species,  of  which  we  have  but  a 
fragment.  Its  characters  are  so  marked  that  we  deem  it 
entirely  safe  to  draw  from  it  the  following  description. 

Shell  of  medium  size,  convolute,  very  rapidly  increas- 
ing in  transverse  diameter.  Volutions  quadrangular,  the 
lateral  diameter  being  nearly  twice  that  of  the  dorso- 
ventral,  slightly  rounded  on  the  back,  and  ornamented 
as  in  the  preceding  species  by  four  rows  of  nodes ; the 
outer  ones  large  and  lanceolate  ; the  inner  rows  small, 
rounded  and  i^uch  more  closely  arranged  than  the 
others,  there  being  eight  of  these  in  the  space  occuj^ied  by 
five  of  the  others.  The  nodes  of  the  inner  rows  are  not 
planted  opposite  each  other,  but  alternate  ; there  is  also 
a line  of  small  indistinct  nodes  arranged  along  the  angular 
edge  of  the  umbilicus,  but  these  do  not  form  a conspicuous 
feature.  The  siphuncle  of  this  species  is  very  small,  and 
lies  close  upon  the  back  of  the  preceding  volution. 

This  species  increases  much  more  rapidly  in  width  than  the  last  : the  nodes  on 
the  outer  angles  of  the  volutions  are  larger,  while  the  central  nodes  are  much  the 
smallest  and  more  closely  arranged  than  those  of  the  other  species  ; and  they  do 
not  appear  ever  to  attain  an  equal  size  with  those  of  the  outer  lines,  while  those  of 
the  last  species  become  the  most  prominent,  and  are  all  arranged  opposite  each 
other - 

Geological  position  and  locality.  In  Coal  measures,  Graysville,  Illinois. 

Goiiiatites  Isatlmwayasia*  ( n.  s.). 

Shell  moderately  small,  discoidal,  much  compressed. 
Volutions  two  to  three,  strongly  embracing,  and  concealing 
about  two-thirds  of  the  inner  volutions ; umbilicus  com- 
paratively wide  and  shallow.  Dorsum  extremely  narrow, 
having  a linear  depression  along  its  centre;  sides  of  the 
volutions  very  slightly  and  regularly  convex  to  the  slope 

* In  honorem  Dominse  Mary  Hathaway. 


CEPHxVLOPODA. 


67 


into  tlie  umbilicus  which  is  more  sharply  curved.  Aperture 
very  narrow  and  much  elongated.  Septa  on  the  sides  of 
the  volutions  strongly  sigmoidal,  with  the  curves  or  lobes 
which  stand  back  toward  the  apex -much  more  sharply 
turned  than  those  pointing  in  the  opposite  direction.  Outer 
shell  entirely  wanting. 

This  species  somewhat  resembles  in  form,  G.  polihis  of  Shumard  (extract  Trans. 
Acad,  of  Sciences  of  St.  Louis,  1858),  but  is  not  rounded  on  the  dorsum;  nor  does 
the  outer  volution  embrace  so  as  to  entirely  conceal  the  inner  ones,  as  in  that. 

Geological  position  and  locality.  The  specimen  from  which  the  above  description 
is  taken,  was  found  in  the  shales  over  the  lower  coal  seam,  more  than  three  hun- 
dred feet  below  the  surface,  at  Lasalle,  Illinois ; but  from  its  polished  appearance,  it 
possibly  may  have  been  drifted  from  some  other  geological  formation  before  being 
imbedded. 

tyitoceras*  giginsteuiii  (n.  s.). 

Shell  very  large,  discoidal  or  nearly  so.  Volutions  two, 
contiguous,  and  sometimes  the  ventral  side  slightly  com- 
pressed by  the  dorsum  of  the  preceding  volution,  rapidly 
expanding;  section  strongly  elliptical,  the  dorso-ventral 
diameter  being  much  greater  than  the  lateral  ; septa 
convex,  distant  one  inch  measured  on  the  side  near  the 
outer  chamber  ; umbilicus  broad  and  shallow  : the  spire  in 
some  specimens  appears  to  be  slightly  more  depressed 
on  one  side  than  on  the  other;  siphuncle  comparatively 
small  and  nearly  central.  The  outer  or  produced  portion 
of  the  last  volution  is  nearly  straight,  and,  when  perfect,  is 
extended  so  as  to  render  the  form  of  the  shell  somewhat 
elongate  ; mouth  unknown. 

Surface,  of  perfect  specimens,  beautifully  ornamented 
by  low,  rounded,  transverse,  rib-like  strife,  which  curve 
back  on  the  dorsum,  and  measure  eight  or  nine  to  the  inch 
on  the  middle  of  the  outer  volution  ; and  by  fine  revolving 
strife,  four  or  five  of  which  measure  a line. 

The  greatest  diameter  of  the  specimen  under  descrip- 
tion is  about  twelve  inches,  and  the  diameter  at  right 
angles  to  it,  ten  inches. 

♦ S»e  note  on  page  76. 


68 


CEPHALOPODA. 


This  shell  (lifTers  from Ci/roceras  (^/Jtaites')  magnijicum  of  Bii.lings  (Canada 
Geological  Survey),  in  the  much  greater  distance  of  the  septa  from  each  other,  and 
in  the  dorsum  being  strongly  convex,  while  it  is  flat  in  that.  It  differs  from  Phrag- 
moceras  maximum,  of  the  Devoniaji  rocks  of  New-York,  in  the  less  convexity  of 
the  septa  and  in  their  greater  distance  from  each  other. 

Geological  position  aad  locality.  In  the  Niagara  division  of  the  Upper  Silurian 
rocks,  Joliet,  Illinois. 

TroclioeiTiis  despliuiaeiisis  (n.s.). 

Shell  very  slightly  trochiform,  suhorbicular  in  outline; 
spire  not  elevated;  volutions  about  three,  expanding  very 
moderately  with  the  growth  of  the  shell,  contiguous;  sec- 
tion sub-elliptical,  dorso-ventral  diameter  greater  than  the 
lateral  ; dorsum  strongly  convex,  ventral  side  slightly 
flattened  or  impressed  by  the  convexity  of  the  preceding 
volution  ; septa  convex,  distant  from  each  other  in  the 
middle  of  the  outer  volution  on  the  dorsum  about  three 
lines  ; umbilicus  broad  and  shallow  ; siphuncle  not  dis- 
tinctly seen. 

Surface  . marked  by  numerous  strong,  obliquely  trans- 
verse angular  or  sharply  rounded  ridges,  strongly  arching 
back  on  the  dorsum,  and  increasing  in  distance  from  each 
other  with  the  age  of  the  shell  : the  spaces  intervening 
those  ridges  are  regularly  concave  ; minute  surface 
character  unknown. 

This  beautiful  shell  is  found  in  the  Niagara  division  of  the  Upper  Silurian  rocks 
of  Joliet,  and  on  the  Kankakee  river,  Illinois. 

<)rthoceras  riislieiisis  { n.  s.). 

Shell  small,  elongo-conical,  tapering  gradually,  slightly 
sometimes  almost  imperceptibly  flattened  on  one  side  ; 
septa  subelliptical  or  nearly  circular,  convex,  distant  from 
each  other  from  one-sixth  to  one-third  their  diameter ; si- 
phuncle cylindrical,  central  or  nearly  so  ; shell  marked  by 
shallow  annulations  about  equally  distant  with  the  septa, 
and.  separated  by  shallow  rounded  depressions. 

This  species  differs  from  both  O.  aculeatum  and  O.  accidentale  of  Swallow  in  the 
siphuncle  being  nearly  central,  and  from  the  former  in  tlie  siphuncle  not  being 
formed  of  a succession  of  hollow  spheres;  but  no  surface  character  of  those  species 
being  given,  it  is  difficult  to  make  any  further  comparisons. 


CEPHALOPODA. 


69 


I have  a specimen  from  Coal  measure  slate  in  Ky.,  which  T take  to  be  the  same 
with  the  above;  and  if  so,  the  siphuncle  is  irregularly  cylindrical  through  the  cham- 
bers and  strongly  constricted  in  the  septa. 

Geological  position  and  locality.  In  Coal  measures  at  Ru.sh  creek,  five  miles  down 
the  Wabash  river;  from  New-IIarmony,  Indiana,  and  in  various  localities  in  Illinois. 

Ortlioceras  kiioxeiisis  ( n.  s.). 

Shell  very  small,  elongate  conical,  increasing  but 
slightly  in  diameter  in  proportion  to  its  length;  septa  cir- 
cular, convex,  distant  from  each  other  about  one-third  of 
their  diameter;  siphuncle  minute,  round  and  situated  cen- 
trally. 

Surface  destitute  of  ornament,  sometimes  polished. 

The  only  perfect  specimen  of  this  species  in  my  possession,  is  a very  small  one, 
and  probably  a young  individual;  but  I have  fragments  from  various  localities  of 
much  larger  specimens,  apparently  of  the  same  species,  which  have  the  septa  vary- 
ing in  distance  from  each  other  from  one-sixth  to  one-fourth  their  diameter;  from 
which  it  is  probable  that  the  chambers  increase  more  in  diameter  than  in  length 
with  their  age. 

This  species  differs  from  O.  moniliformis  of  Swallow,  in  having  a small  siphuncle 
instead  of  a large  one,  and  still  more  distinctly  in  being  destitute  of  the  annulations 
which,  according  to  the  description,  constitute  such  a distinct  feature  in  that  species. 

Geological  position  and  locality.  In  Coal  measures  at  Danville,  Springfield,  Peoria, 
and  Dr.  E.  Hall’s  Mill,  Knox  county,  Illinois. 


GASTEROPODA. 


Biicailia  cliicagoeiisis  ( n.  s.). 

Shell  moderately  large,  convolute,  strongly  trumpet- 
shaped.  Volutions  about  five,  transversely  sub-elliptical, 
slightly  impressed  on  the  ventral  sides  by  the  convexity 
of  the  preceding  volution,  increasing  very  moderately  in 
size  with  the  age  of  the  shell ; the  inner  volutions  increas- 
ing somewhat  more  rapidly  than  the  outer  ones;  outer  part 
of  the  last  volution  broadly  and  rapidly  expanding  into  a 
large  funnel-shaped  circular  aperture,  much  thickened  as 
it  approaches  the  margin.  Diameter  of  the  mouth  nearly 


70 


Gasteropoda. 


doul)le  the  greatest  or  transverse  diameter  of  the  volution 
two  inches  back. 

Umbilicus  broad  and  shallow.  Surface  character  un* 
known.  Specimen  a cast. 

This  species  is  most  nearlr  .-illied  to  B.  expansa  of  Hall,  Vol.  I.  Palaeontology 
of  N.  Y.  1*1.  40,  f.  7;  from  which  it  differs  in  having  ntore  volutions,  a circular 
aperture  instead  of  a lunate  one,  and  in  being  destitute  of  the  carina  possessed  by 
that  species. 

Geological  position  and  locality.  In  the  Niagara  group  at  Thornton,  Cook  county, 
Illinois,  and  in  the  quarries  near  Chicago. 

Fleiiiotoisiaiia  Jiodomargiiiata  (n  s.). 

Shell  rather  small ; spire  elevated  conical,  composed  of 
from  three  to  four  volutions ; length  of  the  shell  equal  to 
once  and  a half  its  greatest  diameter.  Volutions  some- 
what angular,  flattened  above  and  rounded  below,  having 
the  periphery  marked  by  a narrow  flattened  or  slightly 
concave  spiral  band:  outer  volutions  joining  onto  the 
preceding  ones  just  below  the  band;  suture  well  marked, 
scarcely  canaliculated.  C.oluniella  straight,  produced  be- 
low, which  makes  the  distance  below  the  spiral  band  at  the 
commencement  of  the  last  volution  considerably  more  than 
half  the  entire  length  of  the  specimen.  Border  of  the  lips 
thin,  gently  receding  toward  the  middle ; notch  shallow, 
axis  solid. 

Surface  marked  by  coarse  transverse  strife,  of  equal 
strength  above  and  below  the  band,  and  which  are  gently 
recurved  towards  the  notch,  conforming  to  the  border  of 
the  lip,  and  more  abruptly  on  the  spiral  band.  These 
strife,  when  seen  through  a lens,  present  somewhat  the 
appearance  of  projecting  lamellm.  At  the  upper  edge  of 
the  volution  every  alternate  stria  is  elevated,  forming  a 
sort  of  elongate  node,  which  are  sometimes  elevated  so  as 
to  present  the  appearance  of  a band  of  nodes ; the  strife 
between  die  out  at  the  commencement  of  the  nodes. 

This  shell  is  of  the  same  type  of  P.  sulcomarginata  of  Conrad,  from  the  Hamil- 
ton rocks  of  New-York,  but  is  a much  longer  shell,  the  surface  markings  are  pro* 


GASTEROPODA. 


71 


portionately  coarser,  the  nodes  near  the  upper  margin  of  the  volution  are  very  much 
larger  and  commence  at  the  earliest  ages  of  the  shell,  while  those  of  the  other  species 
are  not  developed  until  the  shell  is  nearly  half  grown.  It  is  also  destitute  of  the 
second  row  of  small  nodes  a little  above  .the  revolving  band,  which  forms  a conspi- 
cuous feature  in  P.  sulcomarginata. 

Geological  position  and  locality.  In  shales  of  the  age  of  the  Hamilton  group  of 
New-York,  near  Batesville,  Arkansas. 

Platyceras  cyitolites  ( n.  s.). 

Shell  small,  slender,  composed  of  little  more  than  one 
volution ; beak  small,  pointed,  enrolled,  but  joining  on  to 
the  outer  part  of  the  volution ; dorsal  line  angular,  be- 
coming distinctly  carinate  on  the  outer  part  of  the  shell, 
with  a flattened  space  each  side,  which  gives  it  the  ap- 
pearance of  having  a slight  carina  on  each  side  of  the 
shell.  On  the  short  side  of  the  shell  there  is  one  or  two 
small  incipient  plications,  which  are  not  developed  till 
the  shell  is  nearly  full  grown.  Aperture  angularly  ovate. 

The  direction  of  the  strias  or  lines  of  growth  Avould  in- 
dicate the  existence  of  a broad  shallow  sinus  on  each  side 
of  the  dorsal  carina ; curvature  of  the  beak  in  a plane 
with  the  short  side  of  the  shell. 

The  slender  form  and  dorsal  carina  of  this  shell  give  it  somewhat  the  appearance 
of  the  Genus  Cyrtolites. 

It  is  somewhat  related  to  Platyceras  ( Capulus)  acutirostris  of  Hall,  but  dif- 
fers from  it  in  the  curvature  of  the  shell,  in  the  existence  of  the  carina,  and  in  the 
enrollment  of  the  beak. 

Geological  position  and  locality.  In  the  Burlington  division  of  the  Carboniferous 
limestone  series  in  Calhoun  county,  Illinois. 


BRACHIOPODA. 


Trematospira  matliewsoiii  ( n.  s.). 

Shell  small,  varying  from  subcircular  to  suhquadrate  in 
outline,  length  usually  a little  greater  than  the  width ; 
cardinal  line  broadly  rounded  onto  the  sides  of  the  shell; 
shell  somewhat  ventricose,  valves  nearly  equal  in  con- 


72 


BRACHIOPODA. 


vexity.  Ventral  valve  the  larger,  somewhat  regularly 
convex,  and  having  a hroad  shallow  medial  depression, 
which  apparently  extends  from  near  the  beak  to  the  base, 
where  the  front  of  the  valve  is  prolonged  into  a rounded 
extension  which  corresponds  to  the  elevation  in  the  oppo- 
site valve ; Imak  small,  incurved  over  that  of  the  opposite 
valve,  perforation  small.  Dorsal  valve  convex,  regularly 
rounded,  except  in  front,  where  it  is  elevated  into  a promi- 
nent mesial  elevation,  which  appears  to  become  obsolete 
a little  in  front  of  the  beak. 

Surface  marked,  at  the  front,  by  from  eight  to  ten  small 
rounded  plications  on  each  side  of  the  mesial  prominence, 
which  bifurcate  near  the  umbo,  but  are  usually  simple  the 
remainder  of  their  length;  and  by  seven  or  eight  on  the 
elevation  which  are  fasciculate,  apparently  rising  from 
one  strong  plication  at  the  beak. 

This  shell  is  allied  to  T.  hudsonica  of  Hall,  Palaeontology  of  New-York,  Vol. 
iii;  but  differs  from  it  in  being  more  elongate  in  proportion  to  the  width,  that  spe- 
cies being  usually  much  wider  than  long;  and  also  in  having  the  cardinal  extremity 
more  sharply  rounded,  finer  striae  and  a proportionately  narrower  mesial  fold  and 
sinus. 

The  above  characters  are  taken  from  the  casts  of  several  specimens ; and  it  is  pos- 
sible that  in  the  perfect  specimens  the  character  may  vary  slightly,  but  not  essen- 
tially, as  tho.se  given  are  sharply  and  distinctly  defined. 

Geological  position  and  locality.  In  Niagara  limestone,  Chicago  (Bridgeport), 
Illinois.  I have  also  two  specimens  doubtfully  labeled  from  near  Madison,  Indiana. 

IMsciiia  capuliforma  ( n.  s.). 

Shell  large  for  specimens  of  this  genus,  circular  in  out- 
line, largest  valve  broadly  subconical  or  approaching  dome 
shape  ; apex  prominent,  situated  a little  one  side  of  the 
center ; shell  slightly  inflated  on  the  long  side,  and  most 
prominent  just  back  of  the  apex,  and  contracted  below 
the  apex  on  the  short  side,  giving  it  the  appearance  of  a 
slightly  incurved  beak.  Smaller  valve  rather  deeply  con- 
cave, having  the  nucleus  abruptly  impressed,  not  perfo- 
rate, but  with  a linear  depression  extending  from  the 


BRACIIIOPODA. 


73 


center  of  the  depression  to  the  border  of  the  valve  on  the 
short  side  ; this  depression  forms,  on  the  inside  of  the  shell, 
a narrow  ridge  without  any  appearance  of  a slit. 

" Surface  marked  by  fine  irregular  concentric  lines,  ap- 
parently of  growth  ; no  radiating  strife  visible. 

The  specimens  are  usually  found  in  an  exfoliated  condition;  but  u hen  the  shell  is 
preserved,  it  consists  of  a thick  epidermis  of  corneous  texture  externally,  while  the 
inner  portion  is  formed  of  a great  number  of  very  thin  lamina. 

Geological  position  and  locality.  In  Coal  measures  near  Springfield,  Illinois,  and 
12  miles  northwest  of  Richmond,  Missouri. 


LAMELLIBRANCHIATA. 


^hiciilites  vaseyaiia  ( n.  s ). 

Shell  small,  nearly  twice  as  long  as  wide,  moderately 
compressed,  most  gibbous  on  the  umbones,  broadly  rounded 
at  the  anterior  end,  rapidly  tapering  from  the  beaks  to- 
ward the  posterior  extremity,  which  is  narrow  and  sharply 
rounded ; beaks  situated  about  one-third  the  length  of  the 
shell  from  the  anterior  extremity,  very  small,  closely  ap- 
proximate, pointing  posteriorly;  cardinal  line,  posterior 
of  the  beak,  elevated  into  a sharp  ridge,  ventral  margin 
gently  and  regularly  curving;  hinge  with  from  twelve  to 
sixteen  comparatively  strong  teeth,  about  equally  distri- 
buted on  the  anterior  and  posterior  sides  of  the  beak. 

Surface  marked  by  very  fine  elevated  concentric  striae, 
which  conform  to  the  border  of  the  shell.  Interior  of  the 
shell  (as  shown  by  the  depression  on  casts)  has  a some- 
what strong  and  elevated  ridge  rising  from  beneath  the 
beak  and  passing  obliquely  downward,  reaching  the  edge 
at  about  the  centre  of  the  ventral  margin ; which  charac- 
ter places  it  under  the  Genus  Nuculites  of  Conrad. 

This  shell  is  very  much  the  form  of  Lsda  polita  (nobis),  but  the  concentric  striae 
are  coarser,  and  the  shell  is  not  so  ventricose;  but  the  internal  structure  at  once 
separates  it  from  that,  as  well  as  from  all  other  species  of  Leda. 

Geological  position  and  locality.  lu  shales  of  the  age  of  the  Hamilton  rocks  of  N. 
York,  Batesville,  Arkansas. 

10 


74 


LAMELLIDRANCIIIATA. 


^'iiciila  reetkUJj^ulii  ( n.  s.). 

Shell  small,  subtriangular  in  outline,  somewhat  com- 
pressed; ventral  margin  very  broadly  rounded,  sometimes 
almost  straight,  posterior  margin  sharjily  rounded ; cardinal 
line  and  anterior  slope  nearly  at  right  angles  to  each  other, 
the  former  of  which  is  straight,  and  the  latter  slightly 
curved;  beaks  small,  incurved,  approximate,  pointing  to- 
ward and  almost  terminating  the  anterior  extremity.  Hinge 
line,  on  the  posterior  side  of  the  beak,  marked  by  about 
eight  comparatively  strong  teeth,  and  on  the  anterior  side 
by  four  or  five  teeth  not  quite  so  prominent. 

Surface  marked  by  fine  concentric  strim,  and  by  some 
stronger  lines  of  growth, 

. Geological  position  and  locality.  In  dark  colored  .shales  of  the  age  of  the  Hamilton 
rocks  of  New  York,  near  Batesvilte,  .Arkansas. 

Note. — Dr.  Owen,  in  his  Preliminary  Geological  Report  of  Arkansas,  described  some  dark 
shales  near  Batesville,  as  belonging  to  the  lower  Carboniferous  rocks;  and  the  two  above  spe- 
cies and  the  Pleurotomaria  nodomarginata  (nobis)  may  belong  to  that  formation,  as  I 
have  only  these  and  one  or  two  other  fossils  from  which  to  determine  the  geological  age  of  the 
rocks : they  appear,  however,  to  be  of  Devonian  type. 

Pinna  atlainsi  ( n.  s.). 

Shell  thin,  moderately  large,  conico-triangular  in  form, 
regularly  widening  from  the  beak  to  the  posterior  end; 
valves  strongly  ventricose,  the  greatest  gibbosity  being 
nearer  to  the  ventral  margin  than  to  the  hinge  line,  regu- 
larly rounded  to  the  former,  but  slightly  flattened  as  they 
approach  the  latter. 

Surface  marked  by  distinct  lines  of  growth  which  start 
at  right  angles  with  the  hinge  line,  and  soon  begin  to  sloj^e 
forward  toward  the  beak,  and  become  so  strongly  curved 
as  to  strike  the  ventral  margin  at  a very  acute  angle ; these 
lines  indicate  a strongly  rounded  posterior  margin. 

This  species  differs  from  P.  peracuta  of  Siiumaud,  in  the  greatest  gihhositj'  of 
the  valves  being  nearer  the  ventral  margin  than  to  the  hinge  line,  vdiilc  in  that  it  is 
the  reverse;  and  in  the  flattening  of  the  valves  being  toward  the  hinge  line,  and  not 
below  as  in  that  species. 

Geological  position  and  locality.  In  Coal  measure  rocks  at  Lasalle,  Illinois. 


CORALS. 


75 


S)  iiii«’opora  inultatteiiiiata  ( n.  s.) 

This  species  grows  in  large  clusters  of  long,  slender, 
more  or  less  flexuous,  circular  or  subcircular  corallites, 
which  are  unequally  approximate  on  account  of  the  flexu- 
osity;  at  some  points  in  contact  firmly  grown  together, 
while  at  others  they  are  distant  one,  two  or  even  three 
times  their  diameter.  Tubes  of  connection  irregularly  dis- 
tant, moderately  slender,  and  either  at  right  angles  or 
slightly  oblique. 

Surface  marked  by  frequent  shallow  annulations  indi- 
cating the  stages  of  growth.  Diameter  of  the  corallites 
less  than  a line. 

This  species,  in  the  size  of  the  corallites,  rcsemhles  S.  tabulata  of  Van  Clevk,  Ext. 
du  Tome  V des  Archives  du  Museum  d’llistoire  naturelle,  Paris;  but  differs  from  it 
in  the  corallites  being  flexuous,  while  in  that  they  are  perfectly  straight,  and  in  being 
connected  by  tubes  at  unequal  intervals,  while  that  is  united  at  regular  distances  by 
tubes  which  expand  and  unite  with  each  other,  forming  a wall-like  partition. 

It  still  more  nearly  resembles  S.  perelegans  of  Billings,  Geological  Survey  of 
Canada;  from  which  it  differs  in  the  corallites  being  not  quite  so  large,  the  flexuosi- 
ties  more  irregular,  and  the  annulations  much  less  distinct. 

Geological  position  and  locality.  In  Coal  measures  eight  miles  south  of  Springfield, 
Illinois. 

Cyathaxoiia  piolifera  (n.s. ). 

.Coral  pointed  below,  gradually  widening  to  the  top  in 
the  form  of  a reversed  cone,  bent  in  a horn-like  curve, 
sometimes  nearly  straight ; calyx  circular,  cavity  mode- 
rately profound;  radiating  lamellae  often  more  or  less  dis- 
torted, numbering  at  the  margin  from  thirty -five  to  fifty 
according  to  the  size  of  the  individual;  often  every  alter- 
nate one  only  extends  a short  distance  from  the  margin. 

Columella  or  axis  comparatively  large,  lenticular  in  out- 
line in  its  free  portion,  the  greater  diameter  being  in  the 
direction  of  the  curvature,  and  sometimes  becoming  al- 
most or  entirely  cylindrical  below. 

Surface  marked  by  distinct,  narrow,  rounded  longitudi- 
nal ribs,  crossed  by  bands  or  wrinkles  of  growth  of  irregu- 


76 


CORALS. 


lar  width,  which  in  an  occasional  specimen  present  a few 
short  spines  or  tubes. 

The  usual  height  is  from  one-half  to  an  inch:  diameter 
of  the  calyx  very  variable.  . 

Tliis  species  is  somewhat  closely  allied  to  Tarhmolia  cynodon  of  Rafinesque  et 
Clifford,  Ann.  Gener.  de  Phys.  de  Bruxelles,  t.  v,  p.  234,  1820.  See  Cyathaxona 
cynodon,  MM.  Milne-Edwauds  et  IIaime,  Monographie  des  Polypiers  fossiles.  It 
differs  from  that  species  in  not  being  properly  a spinose  coral;  and  in  the  rare  in- 
stances where  it  does  possess  a few  spines,  they  are  not  arranged  as  in  that  on  the 
alternate  ribs;  and  in  the  form  and  size  of  the  columella,  which  in  that  species  is 
round  and  proportionately  much  smaller  than  in  this. 

Geological  position  and  locality.  In  Coal  measures,  very  widely  distributed  in  the 
Western  States. 

Note. — An  examination  of  more  perfect  specimens  of  the  shell  described  on  page  67,  as 
belonging  to  the  Genus  Cyrtoceras,  may  require  it  to  he  classed  under  the  Genus  Lituites. 
The  departure  from  an  exact  plane  in  the  eurve  of  the  hest  specimen  in  my  possession  may 
be  occasioned  by  accident,  and  I have  no  specimens  which  reveal  the  true  character  of  the 
mouth. 

ERRATA. 

Pages  46  and  47,  for  Athyrus,  read  Athyris. 

Page  63,  insert  Cephalopoda  over  the  words  Nautilus  forbesianus;  in  twelfth 
line  from  bottom,  for  ventrally  read  centrally;  and  for  Pekin,  at  the  bottom  of  the 
page,  read  Canton. 

Page  64,  at  the  top,  for  Gasteropoda,  read  Cephalopoda. 


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